Oh I know I prefer 3.0 to 3.5. Back in the day, I though 3.5 was nothing but a cash grab, and none of what I've read of it -- and I've looked most of the core material -- has changed my mind. In fact, I think I feel more strongly that it was a cash grab through knowledge rather than ignorance.
3.0 added useful material to the game, but a LOT of 3.5's content is bloat with just more races, more classes,, more feats, more spells, more magic items, etc. This in and of itself isn't all bad, but it did bloat the game, and a lot of it was just selling points for books. "In Complete Munchkin, you'll find x new classess, y new feats, and z new spells in the indispensable supplement for breaking your DM's campaign!" Granted, the 5 3.0 splats added stuff too, but they were only 96 pages each and had less space for bloat, where 3.5 books went hardcover and had a minimum of 160 pages. Those hardcovers have some definite filler.
To be honest, 3.0 had junk too, and I admit that I prefer 3.5's revised skills. 3.0 simply had a shorter publishing schedule and its bloat got cut short by 3.5's release. 3.5 had more time to bloat, but that's complicated by its first maybe 18 months where it was doing a lot of updating of the supposedly compatible material from 3.0.
3.5 power creeps stuff too. 3.0 didn't add a lot of new base classes. There was the psion and the stuff from Oriental Adventures, generally new base classes tend to be unique, while character customization tended to focus on feats and prestige classes which I prefer. 3.5 adds base classes more often, in the Complete book, PHB II and so on. A good number of these classes are just hybrids of the original base classes which earns my disdain. There are caster hybrids which I detest as they try to get around the problems with multicasting casters. These classes undermine the non-casters and I'll never allow them even though charopers drop them in the middle tiers and consider them balanced. Then there are the classes that hybridize two non-casting classes which is unnecessary because those characters had fewer multiclassing problems, and those hybrids are generally seen as junk anyway.
Then 3.5 adds a lot of extra magic systems onto the game; there's something like 10 different ones at the end, and 3.5 never needed that. Problems with martial classes in particular were never properly addressed except by adding a book that did all the wrong things: it added new base classes to powercreep the game, addresses the problem by adding a (quasi)magic system and it obsoletes the the material it was supposed to boost in first place.
Weapon sizes and damage reduction changes I'm on the fence about. They make some sense, but they break compatibility.
I laugh at dead levels. Before 3e dead levels were the norm! I can see the problem with prestige classes having dead levels since they're supposed to be better.
3.0 does have a stronger 2e feel it too but edition flavor does tend to shift over time.