some people seem to forget a lot is that a lot of cheap preamp might sound good to the ear, but as soon as you layer them on top of eachother it gets muddy, to bright or just not glue as well together as a $1000+ preamp. Just saying this because of the "firepod" preamp discussion.
If I had to get something on this shootout, I'd go with the Api, SSL or Vintech. The Great River and Focusrite seem to have a bit too much "air" in there.
My list would be:
1 API (really in your face)
2 SSL (again, nice up front in your face)
3 Vintech (maybe a bit too slick, but still great)
4 Great river (wouldn't use this on guitar, think this one sounds very nice, but to "airy")
5 Focusrite (doesn't sound bad or there isn't perse something wrong with it, but to much "air")
Owning any one of them would already make me happy anyway.
First preamp I still want to score is an Focusrite Red, rented it twice for sessions and just fell in love with it.