3B-ST is much better than the older 3B. Ask Bryston for technical differences. I'm sure they will innundate your mailbox with reviews and brouchures. I own a 4B-ST and highly recommend the brand. You can probably find a 3B-ST used for around a $1000. I highly recommend you stretch your budget, or wait that extra few weeks to save some money and get the 3B-ST. I'm sure my peers on this site will agree. Good luck with your purchase.
