Not sure with kids as young as yours that this makes sense for you but my wife and I just ordered a 19' swim spa from PDC
We priced out a pool first and finally settled on the swim spa. Price was < half what a fiberglass pool would have been. Granted it's a ton smaller but our kids are all grown.
The swimming area is still big enough for 5 or 6 people to get in and cool down in the summer. It has a hot tub on the other end.
You can swim in place in the swimming section as that end produces a steady flow of water from 3 powerful jets
Each section can be heated independently as well
I've got the excavation completed (contactor) and just finished the framing (yours truly) so it can be placed below grade allowing the top to be at deck level
Just waiting for delivery here in the next month or so