It plays a little better than I remember GTA IV playing (reminds me of Red Dead), but the real treat here is the visuals. On very high and ultra settings, Los Santos can really trick the eye into looking just ALMOST photo-realistic. The atmosphere, general design, and variety of the buildings really breathes life into the city. It's the first open world game I've played where just driving around and looking at the scenery seemed like a viable way to spend my time. As it tends to be with Rockstar Games, it's very well written too; the voice cast delivers on the script. The online is pretty good; more difficult than I thought it would be. The only issue is that setting up missions can feel like a chore, due to kinda long loading times, and kinda cumbersome menus. I imagine it wouldn't be an issue with a crew of people to play with, though.
Now if only I could have a Saint's Row game that looked as good as GTA V!