[SteveGarward]

We use the E4P every year, on our drive at least. In 2012 and 2013 we have also used them on our flywheels for shooting as well, with a lower CPR encoder disc. In 2012, we did have some issues with bad readings, but it was because of scratched old encoder discs rather than the encoder itself. (Hooking up a logic analyzer showed what was going on the signal when code wasn't behaving as expected.)

Most other issues we have during testing is usually due to an old encoder unit that has more than done its time. Whenever we use new, well handled units we seem to have no trouble. Having said that, everyone is also taught how to handle them and is careful with them.

US Digital has discontinued the E4P though (last year), and has just recently released the E4T as a replacement, so they will be interesting to try out.