Adventure Mamawrote a review of Patagonia Capilene Midweight Set - Infant Boys' on October 4, 2016
Familiarity: I've put it through the wringer
Patagonia Baby Capilene is by far our favorite baselayer for the under two crowd. The onesie and pants are made of the same capilene as the adult baselayers, and performs well. It's warmer than a standard cotton shirt, but more importantly wicks moisture away from baby.
The onesie is key for long hikes with baby in a front pack, where your sweat can cause little ones to get wet and cold without proper clothing.
I also love that baby capilene can be hand washed and dried overnight, so we only need 1-2 sets in each size. We layer both pieces with vests, jackets, and puff pants as weather requires.
The fit is true to a wee bit generous. My boys are tall and outgrew other brands (Carter's, Old Navy, Gap) about two months before the advertised age. They can truly wear the Patagonia outfits as described (B is 9 months old and currently in 6-12 month size). If I could make one suggestion to Patagonia it would be for a second set of snaps on the onesie for a more "grow with you" style.
Patagonia baby gear is pricey but has been worth it every time for our family - we love having the option to get our boys outside in any weather!