I am thinking about buying the game on the xbox store, but i wanted to know if it runs well and generally fun to play on xbox? Also, If its fun for solo adventures (and what the multiplay population is)
There are definitely some differences though:
1) Gear - Diablo has much more varied gear and gear sets. The gear sets look unique and much of the leveling gear does dive you a different look as you progress. WH-I does not. While the gear does create a few different looks, they are not quite as varied. No gear sets.
2) environments - Diablo randomly generates the maps and those maps have more elements and are more varied. They are bigger as well. The environments in WH-I feel fairly static and enclosed.
3) music/sound - the music in diablo is fantastic and the ambient sound is great. The music and sound in WH-I is good but now on the same level as diablo. Voice acting in both games is very good.
4) I haven't played co-op in WH-I but now that they have added it to the game, I'm guessing it adds a lot to the gameplay.
5) diablo has a bunch of little secrets/Easter eggs/fun additional stuff. WH-I does not.
But I still go back to the basic criteria, if you like Diablo and WH40K, you will like this game.