Personally, I prefer the 900 (Seen as I own one I may be slightly biased). However, if you're going to be water cooling then you don't need so many fans and if you on air it only offers two more fans on a case that already had excellent air flow. It looks like someone just got the 900 and streched it and that bubble 20cm fan on top looks ugly and out of place.
If I had to choose again I'd take the 900, also newer revisions of the nine hundred have holes and grommits for water cooling.