Would strongly suggest you hold off on investing on an EMR just yet. Neither of those programs have very usable EMR's for a busy practice. Nextec's practice mgt. functions are advanced, but it's EMR is hideous and inefficient (lots of point & click like the worst of the EMR's out there). Nextec is also locally hosted which dramatically increases your capital outlay and IT costs.
You need to hold off and see how the whole EMR mandate thing is going to play out before you commit to any of these systems IMO. The best looking GUI I've seen is the forthcoming web-based Mentor's Inform Solutions program which is not out of beta testing yet.
If you're a Mac fan, I'd also check out Nopali which is a Plastic Surgery suite for the Mac.