Have been curious about the Ultralight Down series from Uniqlo for a long time, and saw a good number of positive remarks here. So, in searching for a reasonably affordable lightweight down jacket (or vest), I took a shot. Ordered an ultralight jacket, and vest, in size medium.
The pieces that arrived were on target for basically everything but the fit and cut of the garments. Strangely I found they were actually a good deal too large — not only that but they were evidently cut without any curve to the pieces at all … as though all their models are straight rectangular people with 90* angles.
Uniqlo is a Japanese company IIRC, and the models wearing their clothes on their website are rail-thin with no curves of their own. So I *guess* this kind of makes sense, at least insofar as their pieces don't have much taper or curve to them. But, I was quite surprised that a size medium was too large for me. I'm a USA medium in pretty much everything, and would have expected a Japanese-influenced size medium to be trim fitting rather than baggy and boxy.
So … that is all sad / weird. I'll be returning both pieces reluctantly.
As for all other observations that people have made about these pieces — I can only confirm. The bang for the buck is high. Certainly these are not quite as high-quality (and not quite as puffy) as the Montbell UL jacket series; *but* it's remarkable how similar they are to that MB line, when the Uniqlo pieces are about half the cost or even a little less.
So for anyone on a budget, and who doesn't mind what we would call a "boxy" fit — these are a good option.
Just sharing my $0.02.

