Like funky_monks, I'm a big fan of upgrading one piece of equipment, and moving the old one to a backup role. (Never buy a TV for the bedroom; buy a bigger one for the living room, move the old one to the bedroom.) Ideally, I think you would have two identical regs, and they would be the highest quality you can afford. But, I think there are a lot of high-quality "budget" regs out there. Do you really care if your pony's reg doesn't breathe as easily at 130' as your primary? For myself, I plan to buy a pony in the future, and haven't yet decided whether to go bargain, or expensive.