To be honest, I'm not really qualified to give any kind of super technical review of any equipment, especially a lens. There are lots of articles online discussing the important technical aspects of this lens -- and each article that I've found has been decidedly positive. Indeed, the lens is very high quality and feels every bit worthy of its high price tag. It's heavy, in a good way, with all metal parts and an overall premium feel. It feels good and substantial in the hand. I wouldn't want to walk around with this all day, however. But the idea that it somehow doesn't "fit" the philosophy of a compact mirror-less system is silly -- the equivalent lens on DSLR is much heavier. So, it's still compact by relative standards.
To be perfectly honest, I've never been a big fan of any kind of zoom lens, strongly preferring primes instead. But I wanted this lens for some particular purposes that could not be accomplished by my current crop of primes. I needed to get closer to my kids! I needed the extra reach when shooting my girls during their various activities including sports, musical theater, etc. I figured it would be great for candids, too. Yes, I purchased the lens primarily for documenting the most important thing in the world: my two girls.
After a month with the lens, it's performed beyond expectations both in terms of it's intended purpose (kids!) and also for some unexpected other uses, as described below. I thought the 56mm f1.2 was the sharpest, highest quality lens in the Fuji line-up, but this has surpassed it -- and that's especially impressive given that it's a zoom. Overall, if you are thinking about this lens my advice is "go for it." Yes, it's expensive. But, it's still a great value given the positives. Here are some examples:
While the primary motivation for purchasing the lens was to get closer to the kiddos, I decided to challenge myself by photographing a subject that I love, The Walt Disney Concert Hall. Normally, I'd shoot this subject with a more "traditional" focal length, e.g., the very excellent 23mm f1.4. But, I thought I'd try with the 50-140mm which I knew would give me some great DOF and subject compression, which I thought could be kind of interesting.
Below is a gallery of some of my favorite shots of the beautiful WDCH while exploring DOF and subject compression:
Finally, some images to show the bokeh of the lens.