I like both. Personally I think that shorter series are better since you rarely see fillers. I do like longer series like Getbackers for example. I still also watch Bleach but I've been trailing behind since it's starting to bore me like Naruto did. I think Bleach and Naruto would've been better off if they shortened them like not throwing in the fillers and getting straight to the point.

Length doesn't matter to me. It's the quality I go after. If the story is bland and shallow it's a waste of time to me unless it's visually AMAZING (note:akira)... which pretty much is only reserved for anime "movies" now a days.

So a deep story is all I really care about.