Nothing in particular that is not just a personal choice. I use a 660 because at the time I could get them inexpensively used and parts were availible all over the place inexpensively. The Stihl 660 will put a lot more power to the chain than any of the 80cc Echos and the Husqvarna 395 will slap the Stihl around when it comes to power. All that being said, all of them will mill 30” cut in any hardwood availible to me. More power just makes it easier and a faster if things are going well.
There is not much Echo support locally to me anymore, Stihl and Husqvarna dominate my local market.
That would be nice to have an open market for parts.
I never used Husqvarna so I'm not sure on it. If I can get a Stihl 660, that would be great. And maybe down the road get an Echo anyway as a backup or vice versa.
Echo dominates where I'm at, I live in a relatively small town. There is Stihl and Husqvarna available but no official dealers.
Reason why I consider Echo is because the price point. I have a hard time spending $1200-$1300 on a saw when it's going to be for lumber supply for myself.