I now use PPD for all my etching, artwork produced on AutoCAD. I used to use PEC, but they were very slow, will only do A3 sheets (it takes a h**l of a lot of 2MM scale item to fill an A3 sheet!!), they need it on a black background (i.e. etched through = black, unetched =white) and seem to split the artwork into numerous layers, resulting in a lot of corrections being needed.
PPD, on the other hand will do 300mm wide with 150mm minimum length and work with a white background which is what I prefer to work with. Their turn round time is also much quicker.
Jim