I liked the class specific 3e sheets.
The problem with overly specific sheets is that they suck when you want to go outside the parameters they set. For example, Dyslexic Studios made a series of class-specific character sheets for Pathfinder 1e that are pretty amazing (I think they have them for 3.5e as well). So the Barbarian sheet has the rules for rage and boxes in various places to note changes to stats when raging, and the bard sheet includes space for Versatile Performance and bardic performances and spells and such. That's great... if I'm playing a "regular" bard from the core book. But what if I'm playing a Buccaneer bard from Pirates of the Inner Sea, replacing Bardic Lore, Bardic Performance:
suggestion, Lore master, and Bardic Performance:
mass suggestion with various other abilities? Then I'll have to cross out the relevant parts of the sheet and write something in the margins instead, and that doesn't look as good. Or what if we're using house rules where we go back to the better 3.5e rule that bards have X performances per day instead of Y rounds of performance per day like in PF1e? That's also going to cause issues.
If using a more generic sheet with a big box for "special abilities" instead of bespoke boxes for all sorts of class-specific stuff, that sort of thing solves itself. It also teaches players to at least somewhat understand their abilities – writing out "Bardic Performance 13 rounds per day (standard action to start, free action to maintain)" followed by a list where the player notes down the different performances they have access to along with whatever notes they find useful means the player has likely at least read the different abilities at least once, instead of just checking the Countersong, Distract, Fascinate, Inspire Courage, and Inspire Competence boxes.
So my preference is for sheets that only have dedicated spots for things all, or at least most, characters have: ability scores, saves, skills, AC, speed, hit points, and such. The rest can be handled with generic boxes, e.g. "Feats and special abilities". Things many classes share, like spells or companions, are best left to dedicated sheets for that particular thing.