Which VPS in USA can you recommend?

I use linode, amazon ec2, and bigscoots.com. Linode is very stable at a reasonable price. ec2 is very flexible and reasonably reliable but a bit more expensive. bigscoots.com is a great value, very fast and reliable with excellent service. It's nice to have options.

Thanks!

Linode and Slicehost will be the two most common answers. They are similar to each other. I am a happy Linode customer.

You say that performance can be low, so you might look here:

http://www.lowendbox.com/

thanks. Linode looks great!

I am on knownhost.com and so far, so good.