It was approximately 100% of my son's wardrobe for the first several months, and we actually did have him sleep in it for a couple weeks early-on, putting the box on a (large, well-supported) stack of books next to our bed before we moved him into his own quarters. The clothing was unique (in the US) and attractive in a very Scandinavian sort of way, and held up really well. We've passed most of it on to other families, and each piece has probably been used by three or four different kids at this point.
I did a significant write-up on it here: https://www.care.com/c/stories/580/a-year-with-the-finnish-m...
NB: It was on Kinsights back when that existed, and Care.com's redesign kinda botched the formatting. Sorry to myself and others!