I ordered a custom designed skin from Unique Skins a couple of weeks ago. I received it and put it on my phone and thought I would give my opinion of it for those who are considering the same.
Likes:
1. The best part of a custom skin is, well, its custom

. I designed mine so it suits me and my interests. I choose an Alienware theme, even replaced the Blackberry at the top of the screen with the Alienware logo.
2. Very adhesive. This skin really holds onto the phone great!
3. Aparently its scratch resistent. The website shows a video of a guy going to town on his phone with a key. I don't know if this claim holds any water because I sure as hell aren't going to purposely try it.
Dislikes:
1. The skin wraps around from the back of the phone around the sides, almost completely encomassing the phone. Where it curves back the corners pinch a little, creating a burr so to speak.
2. To allow the back door to be pulled off, the skin comes in pieces, one big panel covering the back door, and smaller ones surrounding the phone edges. The panel on the back door is raised a bit and because the skin is a little think (not much just a bit) its raised enough that again its rough to handle. I have been wearing this edge down with use, but when you first put the skin on it feels weird.
3. The screen protector bubbles. They said you can apply it without it bubbling but it bubbled worse than bubble bath in a hot tub (For those who don't know, bad idea.)
All in all its a nice addition. It helps quickly differentiate between my phone and my wifes phone, and although it feels weird I'm starting to get used to it. My only real problem is I bought it hoping to protect it better and without a screen protector its kind of failed the purpose. Now it just looks cool, forcing me to consider an alternative screen protection.
Can't say I'm happy but I can't say I hate it. I spent $20.00 and won't spend it again, but it was a neat bit to try.