I'd been looking for a good used 85 f/1.2 gen I for some time and I was willing to pay $1,500. When Beach Camera listed a new gen II for $1,689 after rebate with free FedEx shipping, I bit.
After a few weeks with this lens, I am very pleased with it. It clearly adds a new capability to my arsenal. The wide-open sharpness and creamy bokeh continue to amaze me. This lens on a 5D, with its low noise at high ISOs, can turn night into day.
AF is adequate in bright light, but poor in dim light. Pointed at a low contrast subject (like a face) in near darkness it will hunt forever, where other fast primes can still achieve AF. This is not a big issue for me, having grown up with MF. However, it keeps me from giving this lens a perfect 10. Perhaps low light AF would improve on a 1 series body.
At the moment, I rank it 2nd among all my lenses (all L zooms and primes, except for the 50), slightly behind the fantastic 135 f/2 and ahead of the workhorse 70-200 f/2.8.
If you need the aperture and can live with slow AF, this lens is among the best. An appreciation for its solid build and impressive looking glass may help ease the initial pain of the big hit on your credit card. Despite the high cost, at around $1,700 I consider it to be a good value.