I bought mine back accident damaged from my insurer, when I heard they were going to sell it for (IIRC) £2300. It cost me about £2K to have it repaired to make it mechanically 100% (I told them not to worry about aesthetics), in an official BMW dealership. If I had done it myself, I could have done it for about £200 less. £700-900 less if I had been patient and bought the requisite parts from breakers yards, ebay, etc. I've ridden mine back to back with uncrashed bikes several times, there's no difference I can detect.
Depends massively on the nature of the damage sustained in the crash, mind...
I like my bike because I can overtake 4x4s down farm tracks with a week's worth of shopping on the back.