I just went through this process. Costs are similar unless you find someone giving away a used one. Delivery on a K&M is about 9 months. I have heard there have been burner issues of late. Not sure if that has been resolved. I was relieved of the decision when I found a 6-year old San Franciscan SF-75 for a song.
I would contact Dan at USRC. He usually has his fingers on the pulse of used ones here and overseas. He can rebuild one and the cost will be in line with a new K&M. Depending on you ability to install one, you can count on double the price when all is said and done.