Flows brake in just like any other binding. The difference is that with Flows you notice the break in cause you are not undoing the strap every run. Every initial adjustment stays the same. They take more initial set-up time but when that time is taken, and they are tweaked after 5-6 days of riding, they are a great and responsive ride. They still have nearly unmatched edge to edge quickness. Also remember that the strap does not need to be tight, only snug.
Another note: in the past it has not been worth it to buy anything from Flow below M11's. They consistently improve in quality every year so this may have changed
I recommend NXT-AT's, SL's (if they really did stiffen those up), SPi's, or Targa's.
Go ahead, drink that kool-aid.
FS: Forum Sauce 142 $200 plus shipping
FS: Flux SE30 $75 plus shipping