Did some additional everyday testings:
All following photos post processed – jpg shots out of Canon 350D.
First of all its a nice close up lens. I like the blurry and a bit charcteristic out of focus feeling of it.
These shots taken with an additional close up lens.
Stopped down you can really call it a sharp lens (for a wide angle). For sure not the sharpest and adapted to my digital crop cam a bit hard to focus on infinity.
Again I didn't use a lens hood, without it produces a lot of lensflair.
So, I'll keep it, and I'll use it regularly. For me it's a nice fun lens with a bit of a own character. And for me as a "mostly prime lens shooter" it's a great new angle. A moderate wide angle on crop – a real wide one on my MX.