My name is Suzanne and I'm a Realtor with Move4Free Realty in Manassas. I realize you posted this question last year, but thought I would still answer it in case you are still interested in the neighborhood. I actually used to live in Sumner Lake for 6 years. It is a wonderful, charming neighborhood with freshly manicured landscaping and a beautiful lake which includes fountains and a large fitness trail. The homes were built beginning around 2003-2004. The schools are Manassas City Schools, which are highly respected in the area. I personally did not experience any sort of crime when I lived there, but I would recommend checking with local law enforcement (Manassas City Police) or searching the crime rates online. Also speaking from personal experience, I had no problems whatsoever with Prince William Hospital. I had all of my three children at the Birthing Center there, and the staff was excellent. Please let me know if you have any further questions, I'd be glad to help!