Well, my recumbent had a malfunction that needs attention before I can commute on it again, and I'll be using that down-time to sort of readjust it a bit too. I was dreading going back to a standard bike, because I knew it takes a while to get used to the riding position. I dusted off my $15 garage-sale mountain bike and put on the lights, panniers and Power Grips. I was expecting a harsh adjustment on my hands, neck and butt.
After the first ride, my neck did feel a bit sore and stiff for a few minutes. My butt got sore a few times while riding, too, and my hands had to move around a lot. But that was about all.
What really suprised me was just how great this old machine is. Brakes stop practically on a dime. Pedaling is powerful and sure-footed. Shifting precise. I think it's an excellent commuter. And to think I had left her out in the cold all this time!
I think the only thing I'll do is maybe change the tires to something smoother, narrower, and higher-pressure....
(I really appreciate the guy who sold me this old bike, I actually talked him up to $15 from $5!)