Steering is much heavier in Gallardo then in F430. That is the difference. Also Lifting system in Gallardo is better for city parking. They are both excellent cars IMO.
F430 feels lighter, specially in downtown driving but, it is a fake feeling. They are very different in feeling which is IMHO very good thing!
Gallardo climate control and heating system is a lot better then one in F430, same for Navi... F430 seats are better then Gallardo's, specially Racing seats.
Oh, I like both of them a lot!