Have a word with your local snapon dealer my one this week had a 18v used gun as a trade in with 2 batterys and charger for £150 that way you know its going to do the job and if the gun stops working in a year or two you can send it back to snapon and have it rebuilt for about £75.
You must be a good customer if the SnapOn guy let you have that, there's usually a queue for the trade in gear.
It's definitely the way to go if you can, one of the guys I share a workshop with has a SnapOn one and it's brilliant.