One particularly interesting argument (to me at least) was from Yerz, who asks... Why do we need more clones? Okay, so he's just bought a Sprinter, but this is a "future" machine, rather than trying to rebuild the old ZX. I found his post interesting as he's done some research and has listed all of the ZX models and clones he can find.
It does raise some interesting problems regarding compatibility... with all of these clones already produced, what should the aim be of future clone-producers. Of course the obvious answer is the 128k ZX Spectrum. But the more models we can reproduce the better, right? I await a machine which can be all of these models... the front panel to switch between them would be huge!