pros
- throttle response
- broader powerband
- sound

cons
- price
- tuning
- price

personally, itb's should be the last mod you do to an already built engine when you're looking for that last bit of hp. you can make the same if not more power with a properly sized intake manifold and tb without the tuning headahces associated with itb's.

if you're in the uk, check out www.jenvey.co.uk the best itb's imo