Let's get the facts straight. If the unit meets emissions but is only certified to stay that way for 50 hours versus 300, what does that tell you about the quality of the engine? Look at the label on the BG55, you will see it says category C (50 hours) and that is why Stihl puts it in their "Homescaper Series". Now the BG85 (or BG86) is a different story, that unit is in their, "Professional Series" and it gets a Category A (300 hours) rating. It makes a difference to Stihl, that is why they have the "Homescaper Series", and all the product you will find there will be Category C (50 hours) equipment. They put it right on their hang tags: "Homeowner"; "Mid-Range"; "Professional". If you don't believe me, go to a Stihl dealer and check it out.
All the ECHO product gets a category C (300 hour) rating because it stays in compliance with emissions for a minimum of 300 hours or longer. You may not care about emissions. Think about it. If the unit meets emissions when it is new, but comes out of complicance at 50 hours versus 300 hours, why is that? The answer is not because ECHO puts more emissions "gizmos" on their machines, or the unit does not last long enought to come out of compliance. Those are ridiculous statements! Talk about ignorance. Go talk to a knowledgeable mechanic at dealer that sells both Stihl and ECHO. They will tell you which units last longer and which units they buy for themselves.
There is no doubt Stihl makes some good product, but you have to pay for it, you have to step up to their "Professional Series". But your beloved Stihl also makes some pretty weak products in comparison as well and that is what you will find those in their "Homescaper Series".