I have the ADH-A700s and find them to sound similar to what a child of Grado and Beyerdynamics would likely sound like, not a bad thing, but they just don't sound all that impressive to me. I would definitely say they were worth the $105 I paid, but I wouldn't pay any more. However, I have put over 20k hours into my Grado SR225s and probably about 5k into my RS1i's and thus I am likely now "tuned" to them.
The best thing to do is to listen to as many manufacturers as possible, back to back, using the same exact setup and songs for each of the cans, and pay close attention to any sibilance (harsh "s" sounds, and the only absolute deal breaker for me as it's so nerve grating), color, missing range, etc. Make sure it's an album that you know better than any other (I use Sigur Ros's Agaetis Byrjiun because I love the music, and it is extremely "Full Range"). If a place isn't willing to let you spend 4-6hrs trying headphones, just leave because they clearly don't care about you getting the best setup for you. Also, I use headphone amps which may be why some don't like Grado's, because the amp brings out a lot of sound that (in the scheme of things, incredibly weak) sound Cards can't push.
Try try try before you buy