Agreed, it didn't take long for me to learn to use the Advantage. But before that I had tried it a few times and got frustrated that I wasn't immediately able to use it. I'm glad I finally took the time though, because I love this keyboard.
I think the advantage is way easier to use and way more comfortable than any of it's 'flat clones'. I've been on one advantage or another for about 20 years. I picked up a used ergodox awhile back because they look kinda cool and I wanted to try out a split. Resold it only a couple of weeks later because it's 'just worse' than an advantage. You hands need to be huge (and mine are) and it still feels like you are reaching all the time. The thumb cluster is way less comfortable.
Since I printed/wired myself a dactyl. Great little kb.