I think I was the first member on TFP to get the Pool Pilot Digital Nano. Installed on July 31, 2010, it is less than 2 months shy of its 4th birthday. I haven't seen a ton of chatter here about the Nano, but I have seen a few vague complaints. The problem with looking to the internet for reviews is that people who are p*&%d off are waaay more likely to go online to complain than those that are pleased.
My review in a nutshell: perfect.
4 years of virtually no effort pool maintenance and very little additional cost. 2 cups muriatic acid per week is about it. Annual inspection of the cell reveals no buildup.
I am a bit of a DIY'er and installation of the Nano was a straightforward, one day affair. A little PVC plumbing and a simple electrical connection in parallel with the low speed side of my 2-speed pump.