Meh, I like it. I haven't read the manga before "chapter" 250+, don't really plan to. However, I've seen the anime from episode 1 to now, and I think I have a pretty good understanding of the series, as a whole.
For the most part, and I know I'm a minority on this, I rather like the filler. We get to expand on the characters within the Bleach universe, much better than in the main story arcs. Conflicts and fights that we'd never see in the main story; and the silliness. Ohhhhh the silliness. The Bleach characters take a day off at the beach. Need I say more?
Shoot, it's not like there's a whole lot going on in the main story episodes, anyway. It seems like almost one significant thing happens in each episode. Compare this to some of the filler arcs, where each episode is its own contained plot as part of the overall storyline. Meanwhile, the main story episodes still suffers from DBZ syndrome, taking multiple episodes for someone to kill someone. This goes on while someone else laments their weakness instead of, you know, trying not to be annihilated.
Any other "drawbacks" could likely be attributed to the other typical drawbacks that can be expected from one of these "shonen-style" anime.