Wow, there is a lot of mis-information on this thread. Stihl is number 1 in market share because they advertise more and sell more to home owners than Shindaiwa, RedMax, or ECHO. ECHO is the number one brand in the commercial market. ECHO, Shindiawa, and Red Max all make better quality trimmers than Stihl. Don't get me wrong, the Stihl equipment is not junk, it is just the others are better. If the Stihl is so awesome, then why do you see so many discussion threads about people having trouble with their 4 Mix machines?
Red Max and Shindiawa do not have the same engines. Red Max is owned by Husqvarna. They make their own engines. Shindiawa and ECHO are owned by the newly formed holding company called Yamabiko. ECHO makes 5 units for Shindiawa and none of them are trimmers. Shindiawa currently does not make any units for ECHO.
Look at the EPA durability ratings on the equipment and look at the warranties offered. The EPA durability ratings are on a label on the equipment. Category A means the EPA and the CARB have certified the engine will run for a minimum of 300 hours and still be in compliance with emissions. Category A is the best rating you can get. Category C is 50 hours. You may not care about emissions, but it tells you about the quality of the engines. That should tell you which equipment you can trust. All the lower priced Stihl equipment is category C (50 hours), right there with Ryobi and the other Wal-Mart type brands.
Also, the dealer you buy from is every bit as important as the brand of equipment you buy. So if you can't decide on which brand, go with the dealer you trust.