After a quick real-life test yesterday, I can happily report that this lens lives up to my expectations Thanks for the great review Dustin, it was your review that gave me the confidence to purchase this lens.
FWIW my copy is made in China...
Thank you. I've strongly considered adding the lens to my own kit for a travel option. I've just done another quick review for a magazine of the 16-300 VC, and I definitely prefer the overall image quality of the 28-300, particularly on the long end. As long as you have reasonable expectations, the 28-300 is a very capable lens.
I think it is indeed a very capable option for travel for those of us who don't pixel-peep too much, in particular if you take into account those important qualities that are often overlooked because most are concerned about sharpness.
These qualities are the good color reproduction, lack of CA, non-distracting bokeh, flare resistance (it is really very impressively good with back lit scenes), acceptable distortion, full time manual focus, good-enough construction with weather sealing and no zoom creep, quiet and accurate AF. And very good image stabilization. I'm especially impressed with the lack of play in the dual barrel, a construction I usually avoid in any lens I purchase.
Finally, it balances exceptionally well on a 5DMkIII body without battery grip and it slips easily into my Lowepro Fastpack via the side-entry flap due to the modest size of the lens and hood.
All in all this lens is capable of taking some very nice pictures which is what counts in the end. So for the sake of portability, the sacrifices one has to make to optical quality are not too great.