The emulators of Atari ST I have seen for the classic Amigas emulate only B&W ST without sound, but some programs are useful under them even B&W games. I think the Atari Sim City was playable on Amiga. Bad about these emulators are that they don't multitask like ShapeShifter and Fusion, so you have to reboot if you want to use some simple Atari Tools, or just to check something under Atari. Having multitasking emulator of ST for Amiga is in better use, than rebooting the A1000.