So I've received my Giant Halfway from the ebay seller. I had some issues at first with the locking mechanism, but loosening the spring seems to have solved that problem, and all is in order now.
The bike is in good condition overall. The tires, of course, show some wear, but they are still good (Kenda Kwest 20x1.50). The only other thing that shows visible signs of wear and tear is the rear rack. Specifically, the bit at the back that attaches to the rear mudguard. This must have broken at some point and is currently attached with electrical tape. It's nothing major and you can barely tell (black tape on black metal).
Beyond that, I must say the bike has otherwise been well maintained. It shifts well. The seller runs a bike shop, and the bike seems to be tuned well. That said, I agree with others that say the brakes aren't as responsive as on other bikes. Seems to take a little longer to stop (and yes, I tried adjusting them ).
I took it for my first ride yesterday. My wife was on her aging Trek that she uses to commute to school and we cruised around the neighborhood and beyond. It was a pleasant ride, and since we're in Illinois it's pretty much flat wherever you go. I noted two things on the ride. One, the ride was about what I expected for such a bike. The seat doesn't appear to be the stock seat, and it was comfy enough, but I may need to find something better in the long run. The other thing I noted is that because it's flat, I spent the whole time on the highest gear. That's a good thing for me if I ever encounter a hill (not bloody likely in Illinois). Overall, the ride was good for me. I don't plan on going more than 3 miles on it at a time so it shouldn't be a big deal anyway.
I like this bike. I'm very happy with it, and you can't beat the price I paid ($226 shipped via eBay). I foresee several train rides in my near future, instead of my current 2.5 hour commute by car to Chicago. It may not be my daily commuter, but I suspect that it will be a regular part of my weekly commuting mix... especially in the winter when I would much rather ride the train than drive.
Thanks to everyone that commented on my other thread. I'll post any updates here. :-)