I've never heard of them, but there are 1000's of screen printers out there that I've probably never heard of
If you need to know if they are expensive, you could just get quotes from a few other screen printing companies and compare them.
If you're super concerned about quality, it might be better to just call around to the local screen printers in your phone book so you can get estimates and have a chance to see their products and printing shop first hand to see the quality.