If you have a good understanding of the MXT, it can be set up to work in Northern Virginia. Depth should be around 6" to 8" on bullets & buttons. I have a friend that uses a DXF up there and gets about the same depth with his. Both of these machines are good for relics.
A Pulse Induction machine is really what you want if you do a lot of hot dirt detecting.
If you have the budget, get the Minelab GPX-4800. That machine properly set up will get you bullets and buttons at 12"-16". It can be set up with some iron descrimination as well. It's a hot dirt, relic hunter's dream machine. (If I have the money, this is the one I'd get)
If that's a little too expensive, either a White's TDI or a Garrett Infinium L/S will be better than a VLF, but they don't have any real descrimination, so you'll dig lots of iron. But up in that hot dirt, sometimes what sounds like iron isn't iron...