Nobody is ever unbiased. Even though I technically have the opportunity to return it, I'm aware that I also
want to like this lens, because a) it's not the type of money I easily cough up, and b) the alternative would be switching systems. Funny thing about that site where I post most of my stuff is that it really allows you to get a grip on the relative irrelevance of gear. The people who take the most stunning shots are typically 5D mkII users with lenses I cannot even afford after selling all vital organs. But I also know how they work... get in a hide, spend days in row to take the perfect shot, throw away every else. A lot of people shooting tripe use exactly the same gear, but simply because they work differently they get different results. Getting expensive gear isn't going to turn you into Frans Lanting, just like getting a late '60s stratocaster isn't going to turn you into Hendrix.
I know a guy who uses a K-3, DA* 300 and HD converter and has the same working style as the 5D shooters who get the loveliest images. His work is quite stunning; check out these, for instance:
IJsvogel - Alcedo atthis 2014-07-18 | Waarneming.nl (OK, I have to admit I secretly don't ever want to see a single kingfisher picture in my life ever again, but still). It's all more a matter of choosing to invest time and effort rather than anything else...