They have a really short recovery arc, so you have to initiate your turn dangerously low. This gives you less time to adjust or bail. Not that swooping isn't dangerous in and of itself, but with proper canopy choice you can improve your odds.
Which in and of itself is not a bad thing, if you are only gonna fly a stilletto. I know people that can swoop the shit out of them. However, when you transition to a katana or velo/xaos/xbrace whatever, and you try that same style turn, you're gonna find yourself one with mother earth after about 90 degress of rotation.
And that would suck.
Is there really so big difference between stiletto and sabre2 in recovery arc?