I just bought one and I like it a lot. I was considering the Switch Easy Nude but after watching the video review, I decided not to buy the Switch Easy one. The Switch Easy Nude case doesn't have a raised edge around the front of the phone so if you drop the phone face down, there's no protection at all. Maccally's MetroCP4 has a raised edge so at least there's some kind of protection.
It's really not that thick. I like it so far. I know these kind of thin cases don't offer a full-blown protections like the Candyshell cases but it's clear and I want to show off the nice looking Iphone 4 design not hiding it.
It's $30, same price as the Bumper from Apple but it's much nicer looking. And it takes care the reception problem. When I hold it, I still have 4 bars.