A few things that I don't like about Nohau:
1. I don't like any emulator that requires you take apart of your PC. It is simply inconvenient for a lazy guy like me!
2. Nohau does make stand-alone emulators that interface to the PC's printer port, however, the box, at least the one I have, is as heavy as my PC.
3. Its Windows software - Seehau51 is not intuitive enough. The way it uses script to define commands is too complicated (for me)!
4. You can't set breakpoints while the code is running. In fact, you can't even scroll your code up and down while it is running.
For the same money you are going to spend, try Signum Systems's UPS-51 ICE if they have the POD for your chip. One thing I like the most is "Performance Analysis". It works just like the feature in Keil uVision2, a very close resemblance!