Actually there is a perfectly good question to use real hardware versus emulation. About five years ago we had some custom software that ran a diagnostic and simulation of freezer systems. This ran on a old 8088.
We decided to junk the 8088 (it died, thank God) and just run the software on an emulator (Virtual PC). The software failed to run properly. Before you ask - no it wasn't due to software transfer. We tried other emulators to no avail.
So there you go. Sometimes you just need the real deal.