This is a great test. As with everything in avalanche safety it's not a magic bullet that covers everything. It is a great tool in your arsenal. I also know that this test was primarily developed in Continental and Intermountain climates. I'd be interested to see how this works for you Maritime guys. So if you haven't tried it, give it a go and let me know how it works for you.
It's definitely replaced the Rutschblock test for me in most instances. Mostly because it's a much quicker test to set up, so I easily can do it in several representative spots in the time it takes me to do a Rutschblock.
This is the most decent video I have found on it. Last year in my class we had a great (scary) result doing the ECT. It propagated and shot out. gapoostQuality 1 shear with lots of energy. It popped the eyes of the class which was great. Love it when you can demonstrate this sort of stuff. Bonus points for this one actually being kind of fun to do.
Hopefully this is new to a few peeps. Give it a try, let me know what you think.
If anyone knows of a better video, please link it up.