I just bought a Jet 1236 and I like it a lot. Based on the pics, that one looks nice. Most of them I've seen being sold as used are well used. Just make sure you open the housing and inspect the pulleys. Those pulleys won't take a lot of abuse and should be cleaned a few times a year. Look for cracks and heavy wear marks.
The foot print of the 1236 is a bit narrow in my opinion. I added a couple 4x4s to the feet to give me a little more height and to increase the foot print by 5 inches. The increased foot print added a lot to the stability. I also did the low speed mod to mine.
I was a bit concerned about buying the 1236 after reading all the on-line reviews. There are a lot of reviews from people who really like it and almost as many reviews from people who hate it. I guess you have to read through them and make your own decision, but the 1236 is working great for me.
Although his asking price is "OK" assuming it's as clean as the pics show, I bet he would take $450 (maybe a little less) for it.