I've only used them for dev of my slide film. It's been fine. Pretty fast service. My current cheap-o dev place of the moment is Spectrum Imaging. They've been pretty fast and the prints are okay (although they don't bother cropping the paper for 6x6 images so you get a square image on a rectangular paper with two wide margins on either side). Seems like there's hidden fees in the postage though, especially when you start getting up to 12 rolls like I did recently but even so, with the weird shipping price it works out to an average of ?5.60 dev and 4" prints per roll either 120 or 35mm.
Peak's pro-side, ProPix, apparently did my wedding photos too as we have the index prints from that, but that was 6 and a bit years ago now.