^ well, F8's are low end brackish not completely freshwater, so if you don't mind setting up a brackish tank then F8's can be a good choice, since they are sort of peaceful compared to something like the hairy puffer...
But at the end of the day it really all comes down to which puffer you like most, since their care levels are all more or less the same, just that some are lurkers, some are active and some need really big tanks while a few might need teeth trimming...