To the OP: I would consider getting the Sigma 30/1.4 for your Canon APS-C DSLR. It has a lovely, smooth character to the bokeh with good central sharpness even wide open. DOF with that lens seems more shallow than one would expect from a 30/1.4 on APS-C. It's one failing is that the autofocus can be hit or miss, but a good copy of the lens will serve you well in getting the look you seek.
This statement describes a specific group of people, mostly on DPReview. It's inaccurate and insulting to refer to "m4/3 people" as if we were a homogeneous group of blinded fanboys and fangirls. Many of us agree that people who find shallow DOF a high priority would do well to look elsewhere. On the other hand, it's an objective truth that the DOF difference between MFT and APS-C is less than the difference between APS-C and 35mm format, and it's also true that the differences will depend on the lenses you choose. For example, someone shooting the Sony 35/1.8 on NEX will not find any DOF difference between that combo and Pana 25/1.4 on MFT, whereas someone shooting kit zoom vs kit zoom or primarily using legacy lenses will find more shallow DOF with the NEX system.
Amin, two things. First, if I sounded insulting, I do apologize, it was far from being my intention ! All that I meant is that, from a personal point of view, and it relates only to MY perception of things, the DOF advantage of APS-C over m4/3 is generally very underrated by people who really love m4/3. I assume they love the format so much (which is a positive thing) the plusses really outweight that particular minus. I remember starting shooting APS-C after several months with m4/3 (and I was using the PL25 almost exclusively !!) about 2 weeks ago, and being litterally shocked (again, in a very pleasant way) at how better my DOF control was. It's not only a quantitative perspective difference, the out of focus areas have a quality that is very rarely seen with m4/3, even when using the best suited lenses (PL25 and Oly 45/1.8).
I don't really see that statement insulting anybody, it's a mere opinion, but I've had numerous enough discussions with m4/3 shooters to think they truly are happily underrating this aspect, exactly the way NEX users (like me now) do like to underrate the lacking lens selection in the format a bit
About the Sigma I totally second your opinion, didn't have the 30 but several units of the 50/1.4 and I absolutely love the rendering of the lens.