I had tried the Flow Runner originals last year on vacation and figured my size to be 37 (I normally run anywhere from 6-7 medium in sneakers, usually 6.5). I didn't buy them then. Went back to my local store today and was surprised the 37 in the same original colorway actually felt just right with no wiggle room (if my feet swell I will be in trouble). So I tried the 38 for kicks, and they have some room to spare. The nylon upper on the 38 was wrinkling due to the larger size, vs the nylon on the 37 was smooth. Needless to say, this threw me for a loop and I ended up walking away empty-handed as I need more time to think about my sizing and whether I'm okay with the wrinkly look. Ugh, first world problems. I am determined to get my Flows eventually!
Of note, the SA did tell me that the new Flows tend to run half a size larger, compared to the originals. FYI for anyone wondering.