I've had the Revo going on six months. I had two heater cores crap out, but E3D 2-dayed them from the UK under warranty. They have gotten the issue fixed, but there are still some of the original problematic heater cores out there. I keep a spare just in case.
The Obxidian nozzles which are the hardened version are shipping soon after a long delay. Just saw that someone is selling knock off nozzles now too, $5 a piece or $18 for all four sizes.
This E3D Quick Change Revo nozzle is designed for easy and quick swap of the nozzle on your 3D printer withou tool or hot tightening.
kingroon.com
I can do a one handed nozzle change as long as the nozzle temp is below 50C. I like it and it is a good system, my biggest gripe is they don't have a silicone sock that covers most of the nozzle face, mine always get PETG boogers sticking too it.