Should I get a case for my Nexus 7?

I really like design of the Nexus 7 and the back feels really nice, but I LOVE the bookcover designs.

Besides personalization reasons, are there any other benefits to having a case? (I doubt that the book design would reaaly protect it.)

Will it make the tablet more clunky and harder to use? I take the Nexus 7 to bed :D and I play a lot of portrait games, so this is my biggest concern.

I also found three really nice products, but I don't know which one to pick:

Portenzo Hardback

Treeglow Streamliner

Dodocase Hardcover

I'm avoiding the ones with the frams, because I don't want to add to the footprint of the tablet.