I'm not too sure what the used price should be but I'll comment on the lens as I owned one for some time...
- It's very well made and looks and feels like a quality bit of kit.
- Optically it's one of the best lenses I've ever used. F0.95 isn't going to be the sharpest you've ever seen but it's perfectly useable and when stopped down I'd describe it as outstanding.
- A plus point is that it'll focus quite close and is useful for close up shots of flowers etc.
It's one of the best lenses I've ever used.