I used them once - got their standard service. They seem a bit expensive, but then their CAD software is free. I've tried EagleCAD, but I found it to be counterintuitive...and I just plain couldn't get it to make custom parts, or even begin to figure out how. ExpressPCB and SCH aren't the most advanced programs, but they do really get the job done well.
But besides that, I was impressed by the product I received. I made a combination board - about 15 separate circuits on one board, which I separated by perforations (just lots of thru-holes in lines), and then cut with a bandsaw.
The boards were well made - accurately drilled and etched, and solder plated very well. Basically, what it said on their site, they delivered exactly.
If you're interested he main circuits I needed were LED boost convertors, little things based on Linear's LT1618, which I'm using to take low-voltage DC and boost it to 35VDC to run a whole slew of LEDs. The little LT1618 needs a heatsink, or else it fries itself instantly, as it can handle a bit over 5 watts. It's only 0.1225 square centimeters too. Right now, I'm able to run 95 red LEDs off of it. It might be able to do another 19, but the breadboard I've got is out of room.