The difference between an emulator and an original piece of hardware is in the mind of the owner. Personally I like the convenience of having everything in one box, a Mac Pro. I sometimes put UAE on the 30 inch display, sometimes on the 24, so I can use the other display to do work. Never driver problems, never hardware issues, it all just works. Sometimes I have AROS or Haiku in one monitor and UAE in the other.
I find I use the old hardware less and less, but I can't yet bear to part with it. But I doubt I'd miss it, the emulation is spot on.