I haven't used a non-staggered matrix layout, only column-staggered and row-staggered. Staggering the columns[1] makes allowances for the fact that your fingers are different lengths, and I like it a lot even though it takes a while to get used to. I suspect I would like a non-staggered layout better than row-staggering though.
Thanks. I intentionally kept the size small since it's not meant to be used as my primary board; I use an Ergodox when I'm at my desk and only use the Atreus when I'm out at coffee shops or relaxing on the couch, so the context is different. Using the fn key for so much definitely takes getting used to though.
[1] - like the Ergodox or my own Atreus design does: https://secure.flickr.com/photos/technomancy/tags/atreus