Hi, new to the forum but I thought I'd dutifully throw in my feedback since this is where I found out about this free case. I ordered the gray and black versions on Saturday, and they arrived here in Brooklyn today. Shipping was $6 for both for me.
I should probably mention that I've only had an iPhone for two weeks and my only other case so far was a $2 thing from Handhelditems.com. Anyway, as far as first impressions I'm very pleased with the gray case. Pretty thin, adds some good texture but not too grippy. I wasn't sure I'd like the ribbed condom-y sides but in person they're a bit more subtle than they appear in pictures. I like that the lip around the front of the phone seems just high enough to be able to lay it face-down with no worry. Fit is tight and secure but comes off easily enough for cleaning purposes. Overall it gives me exactly what I wanted: Added grip with minimal bulk, reasonable drop protection, and don't look too shabby. Very pleased, especially for the price. I'd feel fine about paying the full $15 for this, and trust me, I am a cheap bastard.
The black case is of course basically the same; however, the fit is slightly though noticeably poorer. As an earlier poster described, the fit isn't quite right around the power button, causing the case to be slightly raised on top. I don't consider it a big deal and I'm not sure I would've noticed on my own, but it's visibly worse than the gray case. Also, it had some weird white specks of dirt on the inside. Easily brushed out, but still, combined with the fit issue the black case came off as the gray case's slightly dumber, uglier, down-on-his-luck brother.
Also, this likely says more about my exceedingly poor photography skills than anything else, but over the course of several photos I was able to create camera flash splashback with the black case in a couple instances, but never with the gray case. Odd.