Oh let me share...
Final Fantasy XIV - Cluster****
Wizardy Online - Cluster****
Final Fantasy XIV:ARR - Cluster****
Archeage - Cluster****
I've played plenty more during beta's.
Everyone already knows how much of a screwup FFXIV's V1.0 was, so I'll skip over that.
Wizardy Online - Had servers get crushed and lag out, repeatedly during the first two weeks, people who paid for "services" got partial refunds.
FFXIV:ARR - Hope you made a character during V1.0, because if you didn't you were never getting on those (legacy) servers again. Even to date, the server I'm on STILL does not permit new characters to be created, and it's been just over a year since FFXIV:ARR came out. Occasionally they open slots up when they bulk-ban users, but that's pretty rare. On the plus side... if you're on a server with locked character creation... no bots. Or at least none that you can find. During Launch however, there was hundreds and hundreds of bots that persisted well past the two month point before they started nuking them, and during that time many players who had accrued large amounts of gold (either from V1.0 or from actually playing the game) had their gold balance decimated for some reason that became a beleaguered source of whine all month.
Archeage - Much like FFXIV, they didn't put enough servers online, so everyone who "prepaid", couldn't get on, so those that did get on, camped their login and did anti-AFK activities to ensure they never get booted, thus creating several-hour long queues. This continued all month. Then when they opened new servers, people wouldn't move to them because they already camped land on the founding servers. It took them over a month to start banning bots, which only then did the hours-long queues start disappearing. But on some servers zones there were more bots than players.
Moral of the story is:
1. Do not buy "founders packs" - You will get screwed by not being able to take advantage of the time since you won't be able to log in. In the case of Archeage itself, people had botting scripts designed to camp as much land as possible in the first hour the game was up, so if you weren't the lucky person who bought the 150$ founder pack and was willing to live dangerously to get to the most desirable places first, you were SOL.
2. Do not expect the game to be bug-free or bot-free. In fact, if the game is out in another region before the region you are in, that none of the bugs they deal with have been fixed.
3. If the game is a Korean or Japanese import, assume the game's competitiveness will suffer due to not being designed for 70ms latency (East-West), compared to the sub-20ms Korea and Japan have.
4. There will be DDoS's against the routing infrastructure or login server at launch in order to "screw" people from being able to login/create characters.
One of the reasons I'm less willing to commit to any MMORPG has a lot to do with new games over-reliance on "founder" beta tests. Who in their right mind pays to beta test? If this is how a company wishes to do beta testing, they should be paying the beta testers who find bugs, rather than having the beta testers pay for access (and writing wiki's/guides as they do.) Archeage's founder/beta tests wound up screwing everyone who wanted to play because they needed twice as many servers than they initially rolled out.
The only MMO's I ever tried (non-beta) that didn't horribly fail at launch was Dragons Nest and Fantasy Earth Zero.
*PS Wizardy Online, and Fantasy Earth Zero both shut down due to lack of revenue/interest, both are Japanese imports.