Unfortunately I don't see any difference between emulating an Amiga, and booting Workbench on non-Amiga hardware - there would be if there was some magic way to run 68k code on an x86, but only on a speed basis. The hardware would be a PC, and it would behave like an Amiga (as AROS does) ... note that I'm not talking about booting from an Amiga-on-a-card installed in a PC.
Running UAE on my work laptop Pentium3 1200MHz can blow my 25MHz '040 A3000 out of the water on processor heavy apps, never mind anything else. Audio and Ethernet support is fine, and as stated elsewhere there's no reason you can't replace the Windows shell with UAE in 'GUI bypass' mode, and just use your PC as an Amiga. WinUAE is now the lead version BTW, so yes, it's ahead of even the Unix version. Macs have a 68k emulation layer for old apps in the OS anyway, so I don't know why another emulator might run quite so ineffectually ...
PCs are cheap enough that upgrading the processor & MB for more emulating speed isn't a big deal (the rest is easy to make as quick as the fastest Amiga extras), IMO theres only four reasons to be using a classic Amiga right now - to access old floppy disks, to use the raw 68k speed of a high flying '060, to access PPC programs, or for the love of it. I have my A3000 for the first and fourth reasons.
Oh, and of course there's if you want to use a Toaster!