We were in a very similar position - lived in Lake Highlands for about 6 years, and moved to Flower Mound a little over a year ago. We love it. Its very kid/family friendly, and has been a great place for us. We live in Bridlewood and I prefer the western and northern sides of FM, but there isn't a bad area. My wife works in Highland Village and she and my kids never have a reason to leave a 10 minute radius of our house - we have everything we need here.
I work in uptown Dallas and the longer drive for me was the big compromise, but with the express lanes on 114, traffic isn't too bad (definitely not as bad as the Tollway or 75).
As you noted, the schools are excellent, and there are many good preschool options too. FM doesn't have a highway through it like Frisco, Richardson, Plano, etc. so traffic isn't as congested, and you don't have DART or some of the riff-raff that comes with more congestion.
I didn't realize how much the congestion of urban Dallas bothered me until we made the move to FM, and now I wouldn't trade it for anything. I feel like I can breathe now, and also not worry about my daughter playing in the front yard unsupervised.
Hit me up on any questions you have.