I've been looking at the Generic Classes (Expert, Spellcaster, Warrior) from pg.77 of Unearthed Arcana, trying to decide if I should propose them to our playgroup or not. I know there's a few things that people consider pretty bad in that book, most notably the Human Paragon class, so I could use some input.
I personally kinda like them, but the options for customization make them really powerful. Warriors get all the BAB and saves of Fighters, plus they're not restricted to the Fighter bonus feat list. Spellcasters get basically everything the Sorcerer gets, plus the ability to choose from more spell lists and more feats. I don't see any huge advantage Experts get over Rogues, but they do get to choose what their class skills are.