My results...
Bender 711--If you don't mind the wait, and they don't mind the personal check, so be it. I always want a new firearm by yesterday at breakfast, so I haven't your patience. And if I were the seller, I wouldn't accept your personal check--too easy to steal some checks, fake a signature, etc, etc. You do know that AFTER the check clears, and you send off your firearm in good faith, and then the check turns out to be phony, you are on the hook to your bank to pay the bank back? (You promised the bank it was good when you cashed it.) It's up to you to see to it that the maker of the bad check makes it good.
All of the firearms I have bought long-distance have been paid for with USPS money orders. These can be counterfeited--heck, anything can be counterfeited if it's worth enough to somebody--but what with the USPS Inspectors getting after people who do so, it probably isn't worth it for the price of even quite an expensive firearm. If we're talking many thousands of $$, then probably a bank-to-bank transfer, all financial and guaranteed and legal and formal (not to mention stuffy, time-wasting, and expensive) would be the way to go, but that's quite beyond the scope of the price of any gun you'd just order.
Hadn't thought of the Postal Fraud angle pointed out by Aguila Blanca, but that's one more point in favor of USPS MO's.
Anyhow, they've worked just fine for me.