I have a 540 in my C172N and a 550 in my C210M w/10.3 firmware. Can't say much about the 750 since I don't fly with one. But there are enough buttons around the 540/550 bezel so I can get to most pages very quickly.
I get my air data from a Aspen E5 in the 210 so the 550 makes a great combo for...