I agree that advertised HP isn't worth much - there isn't really any truth in advertising. In fact I'm inclined to like Echo equipment, as I have some old stuff that still works well. To me it is a matter of how they address the two main sources of emissions (primarily unburned fuel in the exhaust) on chainsaws: scavenging losses and poor carb mixture control.
For the first, the problem is simply that the exhaust port is open while fuel mix is flowing into the cylinder. It turns out that quad transfers (and now apparently a branched "Y" transfer) are better at directing the flow away from the exhaust port. But this has been done for years, and still requires other port timing modifications that are not optimal for performance. Strato is mechanically simple, directly addresses the problem by delaying the arrival of fuel to the cylinder, and allows port timing that improves performance. So which is the better solution?
As for the second, chainsaw carbs can only produce a correct mixture at one point - under max load at WOT. Everywhere else they are rich, and often so rich the engine misfires. You can tweak it a little by using an accelerator pump so the idle does not have to be rich, but that is just idle. All you can do for the main circuit is set it as lean as you dare under load. Unless of course you had a carb that produced the correct mixture.....
The best solutions have been developed but they are both owned by Husqvarna, which leaves the others to either pay to use them, try to come up with something better or soldier on with the old approaches. Echo is doing the latter, and that is not appealing to me other than for the price.