I was on the 630 since about November when my 530 took a crap while i was out of town. The 630 took a bit of getting used to but the display, the CGM graphs, etc. were a nice feature. The major complaint was 6 button presses to suspend. Otherwise the 630 was not horrible. I mean, I LOVED the ease of the 530 series menus, two-button suspend, etc. but the 630 was a nice upgrade.
I just got the pre-release 670 last week and decided to NOT wait for the training to make the switch. It's awesome. As mentioned above, the menu is fairly different but the most awesome-ness is how accurate and consistent the new sensors have been. Annoying part is it's now 11 BUTTONS to suspend.
The worst part is the case of boxes of sensors I have for my 630g DO NOT WORK WITH THE TRANSMITTER FOR THE 670g!!! I have 15 or so sensors that I can't use.
Otherwise the pump totally rocks.
I'm on full-auto mode now. It's extremely easy and very accurate. I love it.