The most common complaints I've seen are:
You need a constant internet connection to play!
No, you don't. The only times you need an internet connection are:
When you first download/install the game. (People who buy the disk version can install it normally, I think you still need at least a brief connection so the game can be registered.)
When a patch comes out. Patches are installed automatically if there's an internet connection.
Otherwise, you don't need any internet whatsoever to play. The only downside to not having a constant internet connection is that you won't get achievements. (I think, I could be wrong on that.)
Steam is always running and takes away my CPU's power!
If you have a computer that can handle Skyrim, you can handle the Steam client running in the background. It's not a problem at all. I think it was a lot more troublesome when Steam was first release, but I have it running all the time and I don't even notice it. And it's not like I have some sort of supercomputer either.
Steam has all sorts of pop-ups and annoying things!
There are only two kinds of Steam pop-ups, one for when the client itself needs to update, which happens every once in a while, and a 'news' pop-up that comes daily. Neither affect your game. The news is actually very useful, Steam has a ton of sales, just yesterday I bought the Deluxe version of Oblivion for less than 7 dollars.
Any other questions/concerns?

