MOST STABILITY.. leave a comment

Hey all, I am setting up my grandparents (75 & 76 years old) with there first smart phones. I ran up on a dirt cheap i727 skyrocket and a i717 galaxy note. I want something 4.4 that EVERYTHING works on. Camera, text, calls, data.. . I just don't want something that will be rebooting randomly on them; also these 2 phone have the same chipset so I want to flash both with the same ROM so they can help each other figure **** out. Please leave a comment on what you recommend.
thanks in advance.