He is talking about a 4 stroke motor that runs on 2 stroke mixed fuel.
Don't listen to him, Stihl, Husqvarna, Redmax, Tanaka, Shindaiwa and some others are all comparable. Don't buy on brand name. Buy on what your dealer has and will support. Look at what particular model has the best reviews. People get so passionate about the particular brand they use. It turns into a cult following. Look at the parts that make up their engines, and they are all about the same materials.
I myself prefer 2 stroke. I have had problems in the past with those 4mix hybrids from both Stihl and Shindaiwa. But then again, they ALL have went down hill since the EPA started jacking with the regulations. If you could some how magically come across a new old-stock unit that is from the 90s and early 2000s era, that is where the quality is at from all of the brands.