I would not even want it for free. First of all I would not want stickers all over my phone. Secondly it's not going to protect the phone at all if you drop it. I would go with some sort of bumper or case. There are some clear cases out there that look decent if you're wanting the back and steel band to be visible.
I got the free Zagg skin at my local BB last week. The sales person asked if I bought my phone from them and I told her yes. Even though I got my phone from AT&T. They didn't do any checking so I got the skin.
In my opinion it looks pretty crappy on the phone but I have a bumper on as well. The best thing about the Zagg skin is that it'll protect the steel from getting scratched from debris that gets under the bumper, and it has made my bumper fit tighter so it does not wiggle around at all anymore.
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My 3G reception is great even without the case, as long as I don't cover the gap at the bottom of the phone. However, even though the bars drop when I touch it, my calls don't drop, so it's not a big deal.
I haven't received a case from Apple yet... but I bought one off eBay for $5. The $5 case resolved all my problems and I haven't had a dropped call since I've been using it. And I do use the death grip with the case on as well.