I’ve currently got a Camber Evo 29 and previously had a Camber Carbon 29 (non Evo). The Evo came with Shimano Deore brakes, which perform exactly the same as the XT and SLX versions on my other bikes i.e. brilliantly. The carbon came with Formula T1s brakes, which took a lot of fretting to get anywhere near Shimano performance.
Weight wise, the carbon was at least 2 pounds lighter than the alumium Evo. Handling wise, I guess it depends on your level of experience etc., but for riding trail centres and general trail riding, I don’t think there’s an awful lot of difference between the normal Camber and Evo version – they’re both excellent bikes. I was expecting a night and day difference between the Evo and the normal Camber, but there really isn’t a massive difference in it. I think if you’re into getting a little bit of air, flying off drops and really railing around berms flat out, then maybe the Evo would be the better bet, but if you’re more of a wheels on the ground, normal trail riding person, then I’d go with the carbon Camber – just check that the bottom bracket and headset on the used bike are OK, as IME, they’re not exactly the longest lasting bearings.
As someone has already commented, buying on spec is probably wise, as I found the normal Camber with good components felt better than my boggo Evo (although the latter is being upgraded:))
HTH