Bob,
I have a C270 and it so happened to be the machine I've dedicated for the Tape Project. The Revox C270 was developed at the same time as the Studer A807 in the late 80s and was the last tape recorder developed by Studer Revox. The two machines therefore have a lot in common. Mechanically the C270 is one of the best recorders ever made, not in the last place because of the very smart use of the microprocessor in the tape transport.
There are a few practical drawbacks though. First, all C270s I came across are NAB, not CCIR. Second, there is a lot of (solid state) electronics in the signal path. The machine sounds good, but is limited by it's electronics. I have developed my own all tube electronics for this machine, which really brings out the superb capabilities of the C270. The audio performance surpasses my (unmodified) A810 by far. The third drawback of the C270 is that there are very few of them around. That means if it dies, it is most likely end of story, because the few available spare parts are horribly expensive. For that reason I'm currently retro fitting my A810 with my tube electronics. For the A810 there are plenty of spare parts.
On the positive side, since the C270 has been manufactured roughly between 1988 and 1996, all of them are using mainly Philips high quality components that are significantly more reliable than the components used in the early 80's and infinitely more reliable than the components used in the 70's. Therefore, if you can pick up any operational C270 for a reasonable amount (<$500) it will be a good deal. The EQ is sitting on separate PCBs and is very easily modified from NAB to CCIR.
Arian.