I have both, but prefer Arkham by far. Dracula is a good game, but it doesn't get played often. The good thing about Arkham is that even if you don't have anyone to play it with sometimes, ,you can play it solo and enjoy it a lot.. If you've got all expansions, the number of possibilities and game effect combos is staggering. The game can be quite random, since a lot gets decided by what cards you draw, so no two games are alike, even if you play with the same party of investigators. The real trick is to be able to make the best out of what you've been dealt.
On the downside, Arkham Horror is probably the most card-heavy game I've ever played, so it takes some time to set up and shuffle all decks. And if you play with all expansions, it may prove difficult to keep track of all game elements. In fact, this may be true even with the base game alone.Arkham Horror has a steep learning curve, but it's worth the time and money investment, in my opinion. Once you get the hang of it, the gameplay becomes quite intuitive.
Eventually, it depends what you prefer- a competitive game(Fury of Dracula) or a cooperative game that can be also played solo(AH)
Yeah, my friends and me play it as a 'rpg light', sometimes on workdays when time is too limited for a full-blown rpg. Arkham rocks, Fury is just a nice game once in a while.