Well I'd have to say For-vs-Chevy to a point. The 2 saws are divergent ways of getting to the same destination. On these two Stihl and Husky had an identity crisis and swapped methodologies; the 660 has better top-end stock and is lighter, while the 395 has better torque, better A/V, more weight and MUCH better oiling. I really liked my 660 but contrary to many on here, I found the torque a bit wanting. RPM is nice when you're limbing, but when I'm trying to buck a 4'+/- Burr Oak, or large Hedge, torque pulls the chain. I would imagine a 660 would do just fine as I have seen many photos of individuals using them for exactly that purpose. However, I would prefer to have a bit more grunt. If the 3120 and 880 were out of the price range, personally I would opt for the 395 or the Dolmar 9010/Solo 394.
If I were felling large trees daily and didn't go with either a 385 or a 460/1, I would definitely choose the 660 over the 395 for it's lighter weight. However being a weekend hack, who can basically drive up to the victim(s) of the day, the next big saw will be a 395xp because of it's torque and better A/V setup. If and when I get an Alaskan mill, I believe that it would excel there too. If you have either built by any of the reputable builders on this site, the it's paper/rock/scissors... Hope this helps.