In your opinion, that is. Web site reviews are like anything else... they can be long or short depending on what you want to write about them.
I also think there's an aspect of who you reckon your target audience is. Some people that tend to specialise in certain areas sometimes seem to be writing for people like themselves and will go into the minutae of their chosen subject instead of keeping things fairly high level.
As an example, a 3000 word, detailed review of Kingdom Hearts 2 complete with cross-references to other games might be better placed on a dedicated gaming site whereas a 1000 word overview might be better suited for Dooyoo. My own Helium article, as another example, is probably targetted slightly more at existing review writers rather than the general consumer that might surf by Dooyoo or Ciao that I would usually write reviews for. I reckon the same review would be shorter if that were the case.