Sony 50mm 1.4 vs Sigma 50mm 1.4 - Which is the best?

Hi all,

Im in the market for a prime 50mm lens and i was wondering which is the best candidate between these two? They both seem to produce some magnificent results but if i will be spending approx £300-£400 i would like to get the best out of my purchase. Anyone had good/bad experience with either? Even better, anyone had both so i can receive some realistic opinion?

Please state your feedback realistically as i am more interested to hear honest opinion than to hear biased and supportive arguments for the lens each one owns.

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Χριστόφορος (Chris)
http://www.flickr.com/photos/christophorosp/show