Given that they've set themselves up to be more subjective than their competition, I think they'd fare better if they charged more. Significantly more. Their low sales volume combined with low prices mean that it doesn't pay to upload to Crestock unless you have a library of at least several hundred proven images - those of you just starting out should steer clear of Crestock until you have your 'sea legs', so to speak.
Also, and I have no idea if it's just me, there seems to be very few credit sales lately: every single DL for me this month has been a 25c subscription!