I only use DME and I buy it in bulk (50 lb bag or 55 lb.).
I've never done the direct comparison, but I always thought it was cheaper. The 3.3 lb cans are VERY expensive.
I prefer the DME because it's lighter in color and I feel like I have more control with it. It's my base for all my beers and I adjust body, color, etc. with 5lbs or so of grain.
It's been years since I've done a LME batch, but I do believe that with some of the fresh extract out there you could make a very good all extract batch with LME. I think there's more variety available, including rye extract, so that's a definitely a benefit.