IMO, Maruyama trimmers are the best of the best. They are well engineered and their manufacturing quality is excellent. They are not complex, any shop that has good mechanics can work on them without a problem, and parts are readily available. I sold them in my store alongside Echo, Shindaiwa, Stihl, and Tanaka. The commercial customers I did business-with swore by them, and many of my commercial customers were VERY hard on their equipment.
I have a Maruyama ML23S that is 25 years old. Aside from minimal normal maintenance, the ONLY things that I have done to it are to replace a primer bulb (common with ALL brands) and a broken air filter cover (my fault). It always starts on the second or third pull (it used to start on the first pull before E10), even after sitting for several months. It has been bullet-proof.