Lund tuned cars will smoke AED cars. Shaun gets tune advice from Lund. Just ask him.
For over a year I've read a lot of stuff on both AED (Shaun) and Lund tunes. Both seem to be good tunes, but AED definitely has a large and hard core following.
From what I've read, but not experienced, is that AED has a lot better customer service. I've also read that Shaun is easy to access and down to earth. About Lund, I've read where he's also easily accessible, but I've also read on multiple occasions that he talks down to his customers in a condescending manner, also along with being difficult to access.
If the tunes are really close to each other, I would go with AED for customer service.
Again, this is what I've read in 2 or 3 Mustang/Ford forums.