Yes they do pay on time and they're probably one of the better companies out there to work with. However they only pay $50 unless you make like 30 or more (I believe) conversions per month in which they'll bump you up to I think it was $125. Alternatively you could also just promote them through CJ and get $100 per versus HostGator's $50 and it's every 60 days with CJ.
I agree with ghostvision, traffic is EXTREMELY EXPENSIVE (and that's putting it mildly) it's an extremely competitive niche as I'm sure you already know. Although I haven't promoted them in quite some time back when I was, I was doing fairly well with media buys, I'd say if you're going the PPC route you had better be highly experienced with PPC otherwise you're almost guaranteed a negative ROI.
Anyways good luck to you man