Before I go into my long-winded rant on why I dislike 4th edition, here's my recommendation regarding it: if you absolutely MUST use 4e, get Essentials, not standard. The books are cheaper, the rules are more flexible, and there's a lot of redundancy between the PHBs (Heroes of the Fallen Lands, Heroes of the Forgotten Kingdoms) and the Rules Compendium to make it easy for one person to have all the books and share them among the other players. It's also got all the errata, which is a big deal, because there's pages and pages of corrections that Wizards has made to the 4e standard books.
That said: I don't recommend 4th edition, personally. Yeah, it's relatively easy, but the rules are bullshit. It's grotesquely rigid and yearns to be done through a computer instead of by people capable of improvising.
Reason 1 - There's no middle ground between "combat" and "non-combat" in the power structure; not a lot of room for role-playing and problem-solving elements outside fighting.
Example: The spell "Heat Metal" in every other edition of D&D has rules about, well, heating metal and what happens when someone touches it. You could apply it to anything, including weapons, suits of armor, and other metal objects. "Heat Metal" in 4th edition is strictly a buff that applies only to players' weapons and adds a certain amount of fire damage to their attacks. Of course nothing prevents you from making stuff up, but it's not terribly friendly to newcomers to expect them to know these rules well enough to understand what to do when someone wants to use "Heat Metal" on something that's not a companion's weapon, is it?
Reason 2 - Lots of the powers are bullshit. The "powers" use a structure based on at-will, encounter, or daily usage, which is pretty self-explanatory. You can either use a power all the time, once per encounter (IE per fight), or once per day. It's not a bad system in itself, but a lot of the powers are kind of dumb. Often times they'll make sense in terms of the game's rules, but not necessarily in terms of in-world logic.
Example: The 4th edition Rogue has an encounter power called "Positioning Strike." You make an attack against an opponent, and they move one square. The tiny bit of flavor text explains that this simulates a tricky feint of some sort, like so many swashbuckling maneuvers you might've seen in Robin Hood flicks. Makes sense, alright... why can I only do this once per encounter, though? Is this tied to some mystical power? Am I exhausted or something? In a previous edition, you could try to do this kind of maneuver at any time. Whether it works or not is a matter of the enemy's relative combat skill compared with yours, not the resolution of a power that you activated.
Another Example: The 4th Edition Essentials Druid has a series of at-will powers that work when it makes attacks against opponents. Basically, you hit an enemy, unleashing primal energy with your strike, and channel it into an ally to grant them some kind of buff until the next turn. I absolutely do not understand this; at what point does "hit the enemy" equal "friend gets buff?" I get that this is meant to keep the Essentials Druid in the action as opposed to on the sidelines watching everybody else fight, but I'm having a hard time visualizing him simultaneously casting some kind of spell on an ally while also beating someone with a club.
Another Another Example: The Paladin and the Fighter get what's called a "Mark" mechanic. You mark an enemy, and then they must attack you or else suffer a penalty to their next attack and, in the case of the Paladin, take some damage as well. It's never fully explained why this is, whether it's magic, divine power, or what, but no matter what explanation you come up with there's usually some hole in the logic. Why does my evil sorcerer care about a Paladin's divine challenge? He has no sense of honor. He doesn't care. He's going to do the smart thing, stay away from the Paladin, and pick off the other characters. Why does a rabid wolf care? It's an animal and it doesn't understand a Paladin's challenge to begin with. If it's divine magic that compels the enemy to fight the Paladin, doesn't that mean that it can be countered? I understand the role this has in combat, it attracts aggro and keeps these characters absorbing damage so everybody else is relatively safe--but couldn't they have come up with a more elegant solution than "they HAVE to attack me--because I said so!"? Shouldn't it be the player's job to worry about that?
Reason 3 - The class structure is really rigid and doesn't allow for a lot of creativity. Basically, when you play 4e, the classes are done already. You just unbox them and play. Not bad for pick-up-and-play value, but here's the problem: every fighter you make is going to be exactly the same. Every rogue you make is going to be exactly the same. They follow an extremely rigid 30-level progression with a small selection of powers at each level that dictates exactly what your character's fighting style and role in the group is going to be--regardless of what you as the player perceive it to be. The only way to make a different kind of character? Make a character with a different character class. There's no specific example for me to point to--it's just the way the classes are structured, and it really hurts the game bad.
Reason 4 - Wizards' nickel-and-diming really sucks. Because you have to use a new character class to develop a new concept, you have to keep buying Wizards' new Players' Handbooks or subscribe to D&D insider. The D&D Essentials line is marginally better, with cheaper, easier-to-use books and much more flexible character classes, but the problem is that only about half to a third of the different options for each class are actually available. In a previous edition there were a dozen schools of magic for Wizards to choose from--in Essentials there's three schools--Evocation, Illusion, and Necromancy--and you've got to wait for them to publish more material before you get any of the others, like Transmutation, Abjuration, and Divination.
They sort of pulled this in 2nd edition, providing only specialist rules for the Illusionist in the Players' Handbook, but here's the difference: they still had all the other spells. In 4e Essentials, you only get the spell list for the three schools Wizards cared to put in the book, and they do this with a ton of the other classes, too. Druids can base themselves on a season--but you only get summer and spring, not winter and fall. Clerics base themselves on a domain--but you only get Sun and Storm, not any of the other myriad domains that previous editions contained. Paladins base themselves on a virtue--but you only get Valor and Sacrifice.
Reason 5 - The fluff is unwelcome and annoying. Wizards is really trying to push some kind of nameless default D&D setting with 4e instead of leaving room for players to re-interpret and build their own settings. Like, what's that nonsense about druids being based on worshipping seasons? What if in my world I don't want druids to work like that? And bear in mind that's Essentials--the more flexible, less repugnant version of 4th edition. In the default rules they do even weirder things. What's an assassin? You might think it's some stealthy guy who gets hired to kill people covertly, or with poison. Only if you're talking Essentials, and only if you're a D&D Insider subscriber! The 4e standard Assassin is actually--very specifically--someone who sold their soul to gain the ability to manipulate shadows. This is what we're expected to think EVERY assassin is like.
Meanwhile there's the crazy races. You've got your standards--human, dwarf, elf, halfling, eladrin, dragonborn, tiefling--wait a minute, what the crap are these? In what myth have I EVER heard of something called an eladrin? If you want to know what they are, they're basically a race of super-elves that hail from another dimension. I'm not kidding, this is a standard race. Dragonborn are exactly what you'd think--humanoid dragon-people, complete with breath weapons. And tieflings, why, they're demon-people. Not REALLY demons, not NECESSARILY evil, by any means, but full of infernal power and descended from demonic bloodlines. They're not unbalanced--not really--but all of them feel so out-of-place as standard races in any reasonably down-to-earth campaign setting. It just gets worse when you go into the other PHBs and start talking about things like Shadar-Kai, Goliaths, Shifters, Mindshards, Devas, and Githyanki. What setting am I supposed to use these in?
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Okay, you get the idea, I hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate HATE 4th edition. If you're gonna use it, go with Essentials--it's a lot better than standard. Otherwise, I recommend Pathfinder, by Paizo Publishing. It runs on 3rd edition rules, but with a big update that fixes a lot of problems and makes it a much more enjoyable game. You can actually look them up online, too--just go to http://www.d20pfsrd.com/ and you can read them in their entirety.
