Sigma 30mm lens for Pentax K-7, K-5, K-5 II, K-5 IIs etc

Just wondered if anyone has this Sigma 30mm lens?

I have seen quite a few truly excellent photos taken with this lens. I'm just wondering what you'd consider to be it's plus points and any negatives?

Also how would you say it stacks up against the Pentax primes in terms of quality, resolution, dynamic range etc? Are there any Pentax primes you would say the Sigma 30mm would give a run for their money and compete favourably with? Would you rank this Sigma higher than any of the Pentax Primes and if so which ones?

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Kind Regards,
John
Born in the United Kingdom of Great Britain. I reject EU citizenship.
Pentax Espio Mini / Panasonic Lumix DMC-LX5 / Hoping to get a Pentax K-5 dSLR at some point with a Prime Lens around 31mm!