I'm more of a road bike "if it can go faster I want it" kind of guy so the bikes you're picking do nothing for me... and they both look like mail order bikes? And heavy. I get nervous when the technical information they list is limited to color.

Don't let me dissuade you if that's what you want, but I think they'll be heavy and difficult to get up a hill of any magnitude.

So I guess my advice would be to find a local bike shop with employees that are friendly and knowledgeable and have them help you. Not only can they help you pick out a bike that fits (rather than vague guides like " between 5'8 and 6'2" type sizing) they can also help you keep it adjusted. Your bike shouldn't be shifting gears on its own, that's for sure.

And ABSOLUTELY test a few different bikes out so you can see if you like it... a ride around the parking lot probably isn't sufficient, but if you really like it, you'll be more likely to ride it.

Good luck!