Even though Snotick and others have already given you just about all the info you need, I might as well pitch in my two cents.
I've never had an E72 and the E5 is my first ever smartphone. I used a Verizon enV Touch before. Anyways, like Snotick said the camera is really lacking. My enV Touch shot better pictures with its crappy auto focus and 3.2mp camera. The screen isn't that much of a problem, you only really notice it when watching a youtube video that has many different shades of the same colour, the video gets kind of splotchy (I don't know if that's the right word). Otherwise the phone is great, the keyboard is amazing for sure. There's tons of S60 3rd apps that you can download and most all of them work flawlessly on the phone.
There have also been quite a lot of bad reviews of the E72 from customers on Amazon (I read through tons when deciding on the E72 or E5) and a lot of them say the phone has a build quality. The E5 on the other hand as an amazing build quality, but the plastic chips fairly easy. Yesterday when sitting in my car the phone slid out of my sweatpants pocket and fell to the pavement. It took a hit but the screen is fine, no scratches what so ever. However the plastic body on the side took a few small dents to it. Browsing speed is amazing on wifi and it connects to wifi networks instantly. I haven't really used 3.5g browsing much but the few times I have used AT&Ts network for browsing it was about just as fast as my home wifi on 3.5g speeds.