I have a fair amount of experience on the 430 and like many was rather dubious about the touchscreen 650. However I did my last Instrument renewal on an airplane with the 650 and quickly became a believer
It is a significant advance on the 430 in terms of ease of use and functionality. I later got to fly a 750 and I was blown away.
Garmin has a free download of both units for a touchscreen tablet. If you are interested in buying one test drive the app. Fair warning though, you may find the experience very expensive
