those games are often vastly superior on the ZX.
Cybernoid C64 for example is barely playable thanks to its "so called" collision detection.
Even New Zealand Story in ZX monochrome plays better than all of it's 8-bit counterparts.
Isometric games are sometimes more colourful on the Amstrad yes, but there are only about 2-3 games on the ZX *and* C64 which I would ever prefer to play on the C64.
It's a matter of personal preference of course, but if someone is asking about ZX emulators, i dont think its very helpful to say "play the games on other machines" - the ZX is well covered for emulation on every system under the sun:
I always favoured Spin on the PC myself, but I usually play my ZX games on either ZXDS (since you can download games directly from the emulator) or Fuse on the Mac or PSP now.
Another option of course is to use an online emulator such as:
(this one saves your scores)
almost every game on http://worldofspectrum.org
can be played by visiting the game page and clicking the java icon.