I was mainly on the 42 and only occasionally the 72, but I can't recall any huge differences other than as mentioned about take-off rotation and the need to take the power down gently around 30' on landing....
Didn't have the newer electronics so can't comment, but always felt the 42 was a bit more agile with quicker control responses and hand flying was a bit easier compared to the 72 - especially on visuals....
The other thing that I remember, and maybe it was just the machine that I was working on, was that fuel burn in the 72 was higher enough to notice the difference compared to the 42 - got caught out a couple of times with that when flying unscheduled sectors around the oil and gas fields in NW Africa - but if you're working to schedules with good desptachers and planners, that shouldn't be an issue...
And although I wouldn't describe either of them as a delight to work on ( my personal favourite was the S2000 but that's just me ) both models are quite honest and reliable and if you're comfortable on the 42 you wouldn't have any trouble moving across to the 72....