Yes, thanks so much for the quality discussion. I started training with an HRM back when that was bleeding edge and thought I was totally geeky with my downloading 720i. I see I've not kept up with the technology. OTOH, I'm not going to spend my tire money on a power meter though I can certainly see its utility. One of the problems I see now is that if one has a lot of base and experience, one's HR lags so far behind one's effort that the whole Friel zone thing is fairly meaningless. Which is one of the reasons I've not had much luck with intervals based on HR.
I suppose it would be possible and even a good idea to get a reading on one's FTP simply by noting cog and cadence on a convenient long steady climb at LT. Then one could dial in the various power zones simply by calculating gear-inches and cadence. One wouldn't need a power meter at all if one did one's intervals on the same convenient hill. I think I'll try that.