I guess it depends upon your perspective, and I'm not terribly fond of emulators. There's something distinctly unsatisfying about turning a reasonably fast computer into a pitifully slow one, which is what happens to a PowerPC running UAE. A number of you are claiming fantastic performance. I can only assume that is because of optimisations unique to WinUAE. I have seen worse examples, such as a 1 GHz G4 barely emulating a Macintosh Plus (8 MHz 68000) with Mini vMac. While most of the emulators I've run into do a great job with video, audio support is disappointing. Problems range from emulator X not supporting audio, at all, on Unix implementation Y to timing problems distorting the audio.
The other issue is hardware upgrades. If I want a faster Amiga, I can throw an add-on board into my A2000. If I want ethernet, presumably I can find something which suits my needs. If I want faster emulation, I have to buy a new computer. If I want to add ethernet support in emulation, I have to wait for somebody to add that feature to the emulator. (While I know how to program, I'm not much of a programmer.)
Needless to say, in my books a hardware Amiga is much more interesting -- even if it is based on the 680x0. As for PowerPC based Amigas: I will look at the AmigaOne and Pegasos when the opportunity avails itself. But I want to see one in the flesh. Most of the descriptions and screenshots are woefully inadequeate.