I think most DFW-ites will agree that the top public ISD's (leaving super $$$$ Highland Park out of this list, which is I think #1 in the state anyway) in DFW are:

In no particular order

Flower Mound
Plano
McKinney
Allen
Southlake/Carroll
Coppell
Colleyville/Grapevine

depending on what metric and what "top school list" you are on, all of the above occassionally rotate and outscore each other slightly year to year. BUT all are top districts.

In MY OPINION the problem with "moving west" aka west Tarrant County, Denton, etc, is that those areas are under super growth and have been since early 2000's. That open field down the road, a road which is a two-lane farm road, is a Super Wal Mart in 5 years and that road either stays the same, or undergoes frustrating construction. Ft Worth is also seeing a lot of new apartment complexes pop up and transient construction and oil industry habitants. This trickles into the school system. Coppell, Grapevine, you get a small yard but you get no "pop up" surprises in five years, your neighborhood now is your neighborhood in the future.

Also, the demographics change somewhat. Fort Worth/Denton you will have more of a white guy driving dually pick up crowd (Bass Pro, Cabelas customer, NASCAR fan,), Coppell/Lewisville/Plano you have a indian IT dude driving a Camry crowd. And of course everything in between. Southlake is CEO of XXX mortage company or chief of heart surgery of XXX hospital driving a Lexus crowd. Flower Mound and Keller is dual income mom and dad both work, Odyssey Mini-Van and Accord in driveway, largely anglo crowd.

Fort Worth/Denton family takes a vacation at South Padre Island or Cancun, Coppell guy vacation is Washington DC museums, Southlake is Europe to try to culinary options, Flower Mound is Carnival Cruise or Disney.

Also, check commute to DFW direction. Traffic flow in AM from all locations is largely into Dallas, easterly to South Easterly. PM is back to the west outbound. So assuming a 9-5 commute, living in Coppell or Irving/Las Colinas INTO DFW would be better than any other options.

My OPINIONS only.