.....kinda borderline deal......the older Atomics had an IP creep issue that was later resolved with the 'jet seat piston' upgrade.....you need to find out if the unit has one of the older 'problem' 1st stages....otherwise you'll have to have that replaced, although you can save some $ by installing it at the same time you get it serviced, and it's usually a good idea to have a 'new' (new to you anyway) reg serviced......so you are looking @ $300 PLUS the annual service/jet seat piston upgrade costs.....and if the unit is environmentally sealed 1st stage, add even more $ for the Christolube, which can run something like $30 - $50 U.S. for a 'fill'. Also, I think the B1 went out of production over 2-3 yrs ago, so the reg may be significantly older than you think. I really like my 2 Atomics (B1 converted to M1...and T2)...so I highly recommend Atomics, I'm just not sure you are getting as good a $ deal as you may be thinking you are.