I would choose Dulles Aviation!
For a license or to teach?
After being around the Manassas Schools for a few years, I would NEVER go to Manassas Aviation or Dulles Aviation for a license. Both are part 141, and since the Marines don't put out a contract for bid to teach the IFS students, every 141 school in the area gets Marines.
These 2 schools are SPOILED by this program. They get about $5k for each marine, and they get roughly 8 marines every month, sometimes twice a month. This is a cash machine for them and has basically made their civilian students take the hit. The planes are taken up by Marines all the time, and the CFIs dont want to work with anyone else except Marines since you can make up your own schedule, they are commited to the program, and you dont have to worry about the student running out of money. I was spoiled and I began to hate teaching civilian students.
Aviation Adventures on the other hand is a part 61 school so they are not spoiled by the IFS program. Im still on the aviation adventures email list and I swear every week I sent an email about how they have a new private pilot, a new instrument rated pilot, a new commercial pilot, a new comm-multi pilot. Hell even ATP rated pilot. You know how many times I saw someone pass a checkride in the year I was around at Manassas Aviation? 2. Not because of bad instruction, but because civilian students are just not treated well.
If you want to get a license, go to Aviation Adventures. If you want to instruct, go to Dulles or Manassas, youll be spoiled, but hey, you have to look out for yourself.