Their clothes do wear well -- I've got LuLuLemon pants that are nearly over ten years old and still going -- and I'm a good one to ask because I lived two blocks from LuLuLemon ground zero when it first opened twelve or fifteen years ago. Over the years I've picked up quite a lot from there. I've never had an item die an untimely death, and I put the stuff in the dryer and everything. A testament to the quality of their merchandise is the fact that every single suburban soccer mom in Vancouver's lower mainland owns at least one pair of LuLuLemon sweats and one of their scuba hoodies. I don't think I'm exaggerating. It's like an epidemic. It's one of the reasons I no longer shop there...it identifies me too strongly with a "tribe". Well, that and I can't stand their salespeople. But you can't knock the quality and style of their yoga gear -- it's the best.
And yes, it *does* fit small. Most of it's supposed to be skin-tight. One guy I know lovingly describes LuLuLemon yoga pants as "a bra for a woman's butt". The gals in the shop always try to get you to buy stuff in a size smaller than you think you need, and forget wearing anything but thong underpants with them, because they want the sweatpants to go right up the crack of your rear. As far as the jackets go, they are supposed to fit pretty tight too, and I see a lot of middle-aged mothers wearing them tight enough that it shows their spare tires. So I'd size up. The sleeves are often extra-long too, which lots of people like, myself included -- although one time, they were so extra-long that I had to have them shortened.