They are of course in China. Good for low cost rapid prototypeing and hobby users.
My advisor Daniel recommends PCB Go Go. He says:
Don't design with vias under 0.3mm and trace widths less than 6 mil.
More expensive and not necessarily faster. I read that 2 week turnaround is common.
They have different grades, but "prototype" is $5 per square inch and you get 3 copies of your board.
I ask my friend Andrew, who has been a long time user of KiCAD and he says
We keep the shops American, but they change names/owners a lot. PCB Way is of course awesome, but you're feeding the monster if you go there. There are US shops like PCB way, but a lot of them are fly-by-night. I look for places that do batch jobs. Turn around might be as bad a month.
Some of them just outsource to PCB Way. Ancient Chinese secret!!!!
Tom's Electronics pages / tom@mmto.org