Ive had my snap on almost a year now got it off my dealer, there's not a nut or bolt it hasn't managed to crack off, People rave about them and they are bloody awesome However if you aren't using it regular i'd go with a cheaper model as suggested. I don't think you'd get a 6850 for £200 either one of the older ones yeah probrably but batteries aren't their strong point.
Ive been offered £350 trade in on mine with my dealer against the new 7850. Told him i don't really fancy it though as hes wanting another £300 on top lol tells me it comes with a light (woooo) No good for shooting my rabbits
Chap i work with uses the dewalt TBH if your cracking wheel bolts off, suspension bolts etc it'l be good enough,