The ECU reset works, but plan on about 5 minutes to reprogram that d@mn radio... and you can get around the hesitation a little by throttle modulation - getting out of the throttle a bit can actually give you more power, say, when you're on a constant uphill. Cool weather helps too, so we should see a decrease in hesitation complaints come Fall.
There's one orange MSP near me who's apparently pursuing a lemon-law rebate due to the hesitation, and I don't think he's that far off (I'd support him/her if I knew himher, would like details...). I'm not that frustrated yet and am holding off a month or two to see about Mazda's reprogramming. We should continue to make some stink about it though - heck, RX-8 owners were given a $500 gift card because THEIR cars didn't make the hp promised by the factory, so the precedent is set.
Check boostisgood's thread (the 4-page one); he and chojin are keeping a really good eye on things, have contacted Mazda and everything.
Good luck!
-L