Better!! Better quality than a Stihl!!
Of course, I may be biased...
I'll admit to having no trigger time on the 2165, and I've only had my 2171 for a short time.
But for a 20" bar, the 2165 will be just fine. My 2171 wears a 20 incher, and it's double quick with it.
That being said, though, you basically get another 3/4 horse or so with the 2171, and with almost no weight penalty. (As I understand it, they're the same chassis. SawTroll can confirm/deny that, though.) According to Tilton's website, however, the 2165 engine is supposed to be tuned for a wider toruque curve, so it may have more low-end grunt and a more forgiving powerband. Not that the 2171 is particularly "peaky," however.
But the 2171 also has the quick-release cylinder cover, which I like.
Tilton's site says the 2165 has an outboard clutch, but it also says my 2171 has an outboard clutch, which it does not. If that's important to you, best to verify first.
I love the Jonsered line...I was drawn to it by a good dealer down the street from me. Any Husky mechanic can work on it, too...there's not a terrible amount of difference between the two. The biggest is the straight-across handlebar the Jonny wears, which again I happen to think is more comfortable to run.
Don't know that I've helped much, but if SawTroll doesn't chime in here soon send him a PM. He's probably got the goods on both models.
No matter which way you go, I think you'll be pleased. Jonnys Rock!!! :rockn: