Sigma M4/3 鏡?

聽說sigma出了4/3鏡
而且照出來的品質還不錯
重點是價錢好像滿低的
請問各位大大
覺得值得購入麼?

http://www.43rumors.com/new-sigma-lens-reviews-roundup/

價錢在這邊
http://www.amazon.com/Sigma-30mm-F2-8-Micro-330963/dp/B0076F3RS4/?tag=rumors04-20

http://www.amazon.com/Sigma-19mm-F2-8--Micro-400963/dp/B007F7G6WW/?tag=rumors04-20