I have decided to try and replace my seized Husqvarna 353. I have been looking at Stihl, Husqvarna, Dolmar and Echo. The Husqvarna and Dolmar have single piston ring setups and the Stihl and Echo have double piston ring setups. I have bought a lot of weedeaters, blowers, etc and always look for double piston rings. What's the deal with Husky and Dolmar not using them? Would you expect to get less life out of them as compared to the Stihl or Echo?