I don't know much about Specialized cranks but I would guess they are on par with Trek's "Bontrager" in-house parts. Which is to say, they aren't great but they should be ok.

Disc brakes can have a few common issues. Are they mech or hydro? Most discs tend to rub a little because the pads are so close to the rotor. This doesn't bug most people because it doesn't cause much resistance, and the noise is pretty minimal. Like V-brakes, cheaper discs tend to need a lot of adjustment. Cheaper discs also don't have much stopping power.

As far as the price I think it's not a really fantastic deal, but if the bike is in very good working order then its a fairly good deal.