Another thing to keep in mind is payment method. It seems obvious, but all things being equal, a company that pays by direct deposit is going to be quicker than a company that pays by check. I consider A Closer Look to be a pretty average-speed payer: Their policy is to pay on about the 25th of the month following the shop. But, they pay by check so I always have to factor 3-5 additional days in to allow for mailing to my house (more if there's a holiday). Then, I have to deposit the check into my account. I haven't ever had a hold on the funds, but depending on your bank policy you might run into that.
PayPal is quicker than a check and almost as good as DD, but still: if I get a PayPal payment today, I can zap it over to my account and it will probably be there tomorrow. But technically they had 3-5 days to get it over, so I can't completely count on it being there tomorrow, although I could leave it in the PayPal account and just spend it there using my debit card.
Shopper in California's Bay Area