Both make decent saws. I can't comment on how either company supports its dealers, since I'm not in the business.
I will say that Dolmar dealerships are few and far between in my area. I'd consider them for my next saw, but thwre is no one near by who sells and services them (the one dealer we did have got out of chainsaws altogether, and they were never that good anyway). A good dealer is as important as a good saw, IMO.
John Mc