Greg, last year I bough the Milwaukee M12 rotary tool, which I use with a Dremel chainsaw sharpening jig. Awesome tool. I occasionally use it with the cutoff wheels, too. It's shocking how much work that little battery pack will do. Last year, I had to cut off about 30 1/4" rusted bolts from a trailer I am restoring. The M12 cut those bolts without hesitation, and was still showing the better part of a full charge when I was done.
I've thought about getting the M12 3/8" drill/driver. Certainly would make a handy companion tool for a lot of projects. But I also do a lot of drilling with 1/2" bits, and many of my building projects are with heavy, wet treated lumber and long decking screws, which might be too much to ask of the M12 system. I do love the M12 system, though.
The Ryobi tools themselves are perfectly durable. The batteries, not so much. I've been watching the Xmas deals come and go. Turns out, Ryobi now has three flavors of ONE+ batteries: NiCd, Lithium, and Lithium+. And two sizes of the Lithium batteries. Having trouble finding reliable testimonials about the Lithium batteries.
I've got the following Ryobi ONE+ tools: 1/2" drill, 3/8" drill (2), flashlights (2), 5 1/4 circular saw (2), reciprocating saw, vacuum. I like all of them. I just hate the idea that they need to be fed batteries every year or two. And because I have them split across two homes (residence, cabin), I don't feel I can get by with just two batteries. Really need 3, probably 4, and a couple of the dual chemistry chargers. So, it's either that, or I have to start out all over again with a different brand. Would I love Dewalt, or the Milwaukee M18 system? Sure! But the replacement cost for all the tools I already have is prohibitive.
Still pondering.