I'm not as familiar with Oly gear, but what I said above still stands.
Googling some reviews:
Not a good one for the Oly:
http://theonlinephotographer.typepad...mm-review.html
Not bad for the SLR Magic, but he also speaks better than the above about the Oly:
http://www.stevehuffphoto.com/2011/1...by-steve-huff/
Scroll down for bunch of reviews on the SLR Magic:
http://www.43rumors.com/slrmagic-hyp...ye-bye-noktor/