I tried the Logitech G9X. I liked it (definitely comfortable), but it was very cheaply made. The surface materials rubbed off extremely quickly and it died completely within two years. That turned me away from Logitech forever, they just don't seem to have the same quality that they use to.
I don't know, I think two years is pretty long for a cheap mouse
It's interesting to hear you say this, though. I've had the opposite experience. As long as you're not getting their cheapest stuff, Logitech has pretty darned good build quality. It's not Apple-level, but it's better than the others I've seen on the market. My MX is still in perfect condition after about 20 months (I really can't remember when I got it, it might be longer than that), and the only wear is that the Logitech logo has nearly worn off, but I have very sweaty palms
I also have the Logitech VX Nano, which must have decent build quality because it bounces around in my computer bag with everything else and still works like a champ three or more years later.