I particularly love the Ines de la Fressange collaboration, which seems to be ongoing (it's on its second year now). The quality and cut are worth the extra few dollars. The sizing is different than normal Uniqlo sizing, though. Items run a little larger but the main difference is the cut, which is longer in the torso in my experience.
I have a lot of Uniqlo that I love but it's mostly basics: sweatpants, sweatshorts, half a dozen identical cotton tees, a down jacket. Plus two perfect silk shirts from that collaboration and a cotton-cashmere top. Oh, and a +J (the Jil Sander collab) merino sleeveless turtleneck that is *perfect*.
Fabric quality for their main-line items: the merino is quite good, not as nice as the +J version, but soft and pill-resistant. Their silk is ok but less durable or substantial than Everlane, rather thin and shiny (except the Ines de la Fressange shirts). Their cotton shirts and tees tend to be high quality, with pima cotton so the texture is very smooth.
As for sizing, I'm around a 2 these days, sometimes still a 0 in Gap inflated sizing, and I'd say I'm an XS half the time and a S other times. I've never tried their pants though.
Most Uniqlo tops other than that collaboration are too short and boxy to look good on my long torso. I bought a sweater that is really meh on me because of that fit problem. But, I just discovered that their "long shirts" (almost tunic length) are perfect button-downs for me.
