Other than the usual 'clever' remarks like 'read the POH':
- no crossfeed on the Piper, switch tanks at regular intervals
- only one door - PITA getting in and out
- more likely to float if landing too fast
- manual flaps that deploy rapidly, not the gradual Cessna deployment
- as MJ says, if it's one with the trim on the roof then a bit more getting used to
Other than that - a spamcan.