I avoid check payments mostly because of how I have money tied up. Despite being organized, a payment gets forgotten every now and then. I perform a lot of transactions.
Despite PayPal waiting a day to withdraw funds from my account(s), I find it to be the most convenient method of payment (and payment receipt). I've never had a problem in a PayPal transaction before on a hobby forum such as CGC as a buyer or a seller. I haven't sold on CGC only because I'm not interested in selling any of my collection.
As you probably know, if you are selling in-demand or key books, I'd expect that you'll do well (assuming your prices are fair). I would keep the HOS/Probation List handy, and list that they're not allowed to purchase, if you wish to avoid potential headaches.
Do your homework and good luck!