No, it really isn't. There are only three legitimate DLCs, Gangstas in Space, Genkibowl VII, and The Trouble With Clones. (All three of them are three missions long and you can replay them at any time). The rest are something stupid like one more Homie customization set and another vehicle or two (That'll be $2.99, thank you).
A problem is that the DLCs can only use Pierce, The Boss, and anyone the DLC makes up. It can't use Homies you meet in the game in case you haven't met them yet, and you can't use Shaundi because the game assumes you might have taken the "Revenge on Killbane" option that kills Shaundi.
Genkibowl VII is ENTIRELY more Genkibowl minigames with no substance to them. I don't think there's anymore outfits or vehicles, just three minigames. Escort Dr. Genki -- similar to the Tiger minigame, except you have to kill people instead of staying alive. More Genkibowl tournaments -- which are just longer and harder. And Yarngasm -- which is another Mayhem minigame where you play a giant, mobile crushing vehicle with no weapons.
Gangstas in Space is way too much of a fucking drag to be worth it. Missions last up to or around forty-five minutes of just straight up driving around killing tons of people with horrible guns you are forced to use, and the checkpoints in them are murder-inducingly stupid. A few jokes that are pretty good, one good character that you get as a Homie, and some rather okay vehicles. You get a Space Bike, which is exactly the same as the Jet Bike (the one you can possibly get on the STAG infiltration mission), and you get another VTOL-like vehicle.... It's okay, but the missions are so badly designed and the rewards aren't worth it.
The Trouble With Clones is easily the strongest of the pack, I think it's the only one worth getting. Get it if you've played Saints Row 2, but you don't need to have played it to understand it. The missions are A LOT of fun and are absolutely hilarious, have a lot of memorable scenes and more of the Saints Row "I can't believe I'm fucking doing this, this is so cool and unexpected" moments. I won't spoil it, but if you aren't getting it, look it up. I think the only rewards for it overall is a Brute Homie and a gun that shoots bees (which is similar to Fart in a Jar or the Stun Gun).
