My first time at Whistler, the biggest problem I had was handling runs that take 25+ minutes to get down instead of 4-5. Thighs were killing me!
I've had Flows for a couple of years. I also have 390's on my other board. Hopefully what I'm going to say is equally applicable for women's bindings. You'll have to decide that.
Flow's are a lot more trouble to initially set up, because you have to get the proper level of tension in the 'I' strap. Once you have it dialled though, it probably only needs a small adjustment every couple of days. The amount of time that takes though is way
more than made up for by the time you save at the top of the run. I personally can kick my back foot in, reach down, and snap the binding shut without ever coming to a stop. But even if you do stop, you don't have to sit and it takes maybe 3 seconds. Skiers spend more time transferring their poles to the proper hands and putting the wrist straps on.
As far as "less control", opinions are divided. Which should tell you that the difference (if any) is subtle. If you compete professionally or semi-pro, I suppose it might make a difference. The big difference though is that at the end of the day your feet aren't aching, because the bindings don't have to be as tight (because of the large contact surface).
One place though where Flows really are a PITA is strapping in on a significant slope. You can't sit down and strap in, you have to turn to face uphill and kick in in an awkward semi-crouch. That's why I have the 390s on the other board -- for park.
OTOH the new NX2s probably take care of this problem because you can strap in the traditional way if you want. Haven't seen them personally yet.