You are getting some huge generalisations here for instance comparing old C172s and new PA28s.
Both aircraft have been on the go for around 50 years and there are dozens of versions of each.
Most of the PA28s are very easy to fly. They're not all floaters. I would be surprised if you don't convert in an hour or two at the most if the engine is 140,150,160 or 180.
Backpacker and Adam have covered the requirements very well.
D.O.
Last edited by dont overfil; 1st Nov 2012 at 09:50.