I got the 17-85mm as a kit lens with the 30D, meaning to sell it and buy something better, but ended up keeping it.
Pros: Excellent walk about range, good sharpness in the centre, and very reasonable IQ, cheap - if you buy used and shop around.
Cons: Build quality isn't bad, but not great either. Slow, serious distortion below about 24mm (correctable in post processing), some copies have edge sharpness and CA issues. Mine is quite acceptable, so this seems to vary.
Ultimately, it depends what you compare it with, and how much you're prepared to spend. The 15-85mm is a better choice, and the 17-55mm is a far better choice (if you can live with the reduced range), but both are significantly more expensive. I suppose you get what you pay for, but the 17-85mm isn't too shabby and it's not the dog it's often made out to be. Just be aware that these are all EFS lenses so they don't come with lens hoods, unless a previous owner bought one. They're pricey, for what they are.