I recently made a mount for the 660 in my RV-8 so that I can use it to display ADS-B data from my new GTX-345, and it's a very nice replacement for the 496 - as long as you are comfortable not having XM weather anymore. Great display, logic the same as the rest of the touch screen Garmin equipment, and much more modern than the 496. Very nice unit.
Of course, for full disclosure, I still have an original 696 in the cockpit (because I do a lot of testing) ... but I find that I am rarely even acknowledging the boot screen on some flights anymore....
Paul F. Dye
Editor in Chief - KITPLANES Magazine
RV-8 - N188PD
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)