Yes and no...
I still want to see an emulated Amiga run as nice as a Real one. Try some demos.
I've seen problems similar to the ones seen by amiga_3k. But I believe it is a matter of how fast your PC is, and what you expect of it.
In the other hand, it is easy to get how many RAM you want in the emulator. AHI and RTG will be easy also. My A1200 is still standard and I would have to spend some money to have a nice setup. If you compile stuff, you can notice the speed advantage of the emulation also.
My opinion: have both :-D Unless you buy a super powerful Amiga
