There was also something about these books, I can't quite put my finger on that missed the spot for me. I recall loving the old 2E brown books (especially the complete bard), but the 3E Completes just didn't do it for me. And I would be lying if I said I knew exactly why that is.
I had responded to this earlier,. However, my post was, apparently, eaten when the site had problems earlier today.
I too prefer 3e (provided I stay away from most WOTC supplements including the race and class splats) and, also, prefer the 2e Complete Handbooks to WOTC's Complete Books
I like the 2e focus on a specific class. They covered a lot of archetypes from cultures and media. As a DM, it helped provide PCs and NPCs meaningful background and cultural differences (e.g., armor and weapon proficiencies) for settings with multiple cultures and/or social levels. It also provided ideas for more themed settings.
Another benefit was that 2e was about customizing the clases at first level to meet a cultural or background concept. While 3e had the tools to do this better (tailoring clases, the DMG variant spell lists and swapping class abilities), there were few examples to help out the DM until Unearthed Arcana. The result was that, in 3e, many DMs were either too afraid to tweak classes or too lazy and the unwillingness to tweak classes meant players had to jump through hoops via multiclassing and/or prestige classes to meet a concept that should be viable at level one.
Finally, the more indepth look into a single class of the 2e books meant that there were more options in the book for that class. The benefits were that
a) You most likely didn't have to wait for a concept to be covered for your class (e.g., 3e sorcereor heritage feats scattered among 3e books)
b) You had less books to refer to or carry to access material for your class.
c) For myself, I was likely to find enough worthwhile content in the 2e books to warrant buying the books even if there were some lousy content (e.g., the Greenwood Ranger and Bladesinger kits). In contrast, with 3e class supplements, I was likely to find only a few pages of worthwhile and passed on them all