Mine arrived in the post yesterday and I'm quite happy with it. I can confirm it autofocuses very well on a Canon 500D. I wasn't sure about the new STM and what impact it would have on a camera which can't use it.
I'd say no impact. I understood it not to have FTM but I couldn't confirm that it can with the shutter half pressed. I'd never thought of trying that. It can manually focus as it has a switch.
The photos so far are sharp at F2.8 and the bokeh is nice and pleasing.
It is small but for some reason I thought it might be even thinner. It's quite solid to hold not heavy by feels substantial for it's size.
I'd agree with E-Photozine as in what it is for? I'm not sure why I bought it. I think I like the idea of a Prime Lens between the 28mm and 50mm ones I have. I think it would suit a full frame better and it would be wider.
64mm is an odd focal length.
Still so far I really like it. I haven't taken any spectacular photos with it but it's given me no worries in terms of the photos that are coming from it.
I feel primes force me to think more about the shot and where I am positioned which improves the photograph.
When I get around to it I will post some examples on my Flickr Page www.flickr.com/fergalocallaghan