I have a Samson Go. I got it for Skype,etc. It clips onto my laptop screen and I have to say I'm amazed how good it sounds. I'm sure a Blue Yeti would sound better, but I couldn't say how much until I tested it.
I bet there are side-by-side comparisons of popular USB mics on YouTube. The sound on YouTube itself is not stellar, but the comparison might be valid. It costs about twice as much (maybe a little more) but I doubt it's twice as good. Though it's a lot better, I'm sure.
If I had some more serious use for a good mic--music, singing, even an audio blog, I'd probably go for a Yeti. I think they're both good value for the money.