The qwerty keypad is a big draw for me and as much as I love my iPhone, a touch screen qwerty keypad just isn't as good as 'proper' keys (in my opinion!). The 5MP camera is significantly better than previous E Series cameras, although not in the same league as some N Series devices.
The Optical NaviKey is an interesting new feature for navigating the screen. It takes a bit of getting used to but with some practice it's a nice enhancement to the usual 'click to scroll' function.
The S60 software does seem a bit dated after using the iPhone but it does the job, suitably enhanced with Handy Taskman. The faster processor seems to make a difference, with much speedier performance than on my previous E Series devices.
A couple of nice E63 features (that weren't on the E71) have been carried through - the 3.5 mm headset socket (of course!) and the space bar torch feature.
Overall, I think the E72 is a worthy successor to the E71, especially if a decent qwerty keypad is a must for you.