Wow! I've never seen such a clean 700 series! Congrats!
My 770 doesn't look like that at all. Neither does out 750 at work. But they do a lot of work. Mostly mowing heavy grass w/ rotary cutters. I've never had any trouble getting maintenance parts at my dealer and haven't needed anything besides belts, hoses and filters. Might need a battery this year, but 15 years is really not too bad.
I could never get rid of the 770, its just too darn reliable. It has never failed to start and run in the coldest weather and always performed flawlessly.