Billy Royals are really nice. A friend has one, and the leather and silver are gorgeous. Schneiders sells the full line. I hear they're very comparable to Billy Cooks, leather quality wise, and they have a wider range of options. I'm not sure what luck you'll find on eBay though...No one seems to want to sell theirs.
My Circle Y is super comfortable and balanced. Unfortunately it doesn't fit my horse anymore, so I'm having to sell it. I'm pretty sure I'm buying a Billy Royal once this one sells.
EBay will probably be your best choice for something of good quality.
Billy Cook (the real one made in Sulphur, OK, not the one made in Texas. It's a fake.), Billy Royal, and Circle Y are what I suggest.
"You're just as sane as I am."~Luna Lovegood.