It's soft focus, not out of focus. A sharp core, surrounded by a variable halo of blur.
I bought a used one a few months ago, but sold it fairly soon after (they sell very quickly BTW!). I got it to do some soft focus flower pictures but it didn't work out because I needed a small aperture for depth of field, and when you stop it down beyond f/4 it starts getting sharp again. Switch out the soft focus effect, and it's a very sharp normal prime.
The soft focus effect is unique. You can get close to it with expensive filters like Zeiss Softars (£200 each) though I've never seen a Photoshop effect quite like it. But you can get close of course, and given the limitations of that lens in terms of fixed focal length and only two or three f/numbers where the effect is really visible, doing it in post gives you a lot more options.
For female portraits and romantic looking stuff, it's great. A good wedding lens I'd have thought, doubling up as a fast prime. The guy I sold it to one here (it went within hours) was going to shoot some fashion I think, which sounds spot on for something different.