I’ve done over a dozen boards at OSHpark and they have all been flawless and very high quality. So you will not be disappointed in the service. The increase in volume (with BatchPCB) also translates to faster turnaround time.
A few notes: It’s easier if you use their CAM file to generate your gerber files. http://magic.laen.org/pcb/LaenPCBOrder.cam
and their DRC file for checking : http://oshpark.com/LaenPCBOrder.dru
With the extra load, their servers may take a while to process a complex board – but it’s worked great for me.
regards, mox