The only downside to Dominion is the fact that it becomes a cluster-blam!- of power weapon hoarding, unless, that floats your boat... Invasion had many balancing issues pertaining the Spartans Vs Elites, and Invasion Slayer is still a 50/50 in my mind. Plus, the maps for Invasion Slayer were terrible, and having only two maps for regular Invasion was a letdown. I feel like I want to give it to Invasion, but Invasion has many more drawbacks that come to mind compared to Dominion. This is actually a much harder choice for me then it should be considering these are the only two gametypes that kept me interested in these two games. If Invasion had better support from Bungie, it would be a no-brainer, but as is, I can't say that either one is more enjoyable IMO.