FWIW, I quite like the sound of the Alpha Dog with the new tweaks/taming kit. I always found myself wanting to EQ the top end of the Mad Dog (2.0 through 3.2, haven't tried Pro) and the Paradox (early model, and not Slants). If you've read much about the AD, my pair has two of the "dots" on each channel, and usually one felt disc in each does the trick for me. I think there are some further front damping tweaks that could improve the sound, which I'm experimenting with, and I actually tend to use different materials than the felt discs provided (or sometimes use my material with the felt). But I think most people would be very happy without taking those steps.
Keeping in mind personal tastes, equipment (I generally run the AD from a NOS DAC and a warm, vintage receiver), and product variance, YMMV. The Schiit offerings for amps will provide some good options.
Keep the two Paradox headphones in mind as well. If you're considering open headphones, that will give you a lot more options in your price range.