haven't had the best luck with the ryobi LiIon batteries (2 of 4 failed within 2 years), but i have a TON of the tools and have been satisfied with all but the 1/2" impact - its very weak compared to the current competitors 18v impacts. i ended up getting the milwaukee 18v impact and am planning to replace my ryobi stuff if it dies or if the remaining batteries fail. the tools themselves have held up well to quite a bit of use - recip saw, stapler - literally nearly 10K staples driven at this point, drill, little circ saw, their rotary cutter thing - sort of a dremel looking deal but you can side-load the cutter/drills, caulker - laugh if you want, but pumping a case of caulk in a day ***** with a 'normal' gun, not sure what else. i think the milwaukee stuff is made better and their battery tech seems to be better than the rest, although you certainly pay a premium for it. on the upside for milwaukee, they have an ENORMOUS range of M18 and M12 stuff and are fairly quickly migrating to the brushless tech.
overall, i'd guess most people (including myself) would find the ryobi stuff quite serviceable..but the milwaukee is better
ahm