Having played both Risen 1 and 2 I have to say, this game looks amazing. Even though in my opinion Risen 2 wasn't as good as the first one, Risen 3 is everything Risen 2 was and more. It has better combat, better character progression, 3 interesting factions instead of 1 and a half factions (referring to Inquisition faction; muskets vs voodoo magic, seriously, what's the obvious choice?), many more spells that actually have great usefulness like they did in Risen 1. I'm not sure yet how it stands compared to Risen 1, but for me, even though it will have a hard time beating Risen 1, it still is worth the playthrough at least once. Also, looking at the factions, I will have to probably do 3 playthroughs with each faction, they are that awesome.
You can check out my first impressions and walkthrough of the game HERE.