I've been running both there is no difference in the saws power in the wood we have in my area, the Husky is smoother to run but is a lot heavier to work with my 7900s are a much nicer saws to work with then the 390XP. If I had it to do over and know what I know now I would not have bought the 390XP saws at all.
Interesting to hear, thanks. I would like to try a 390 for interests sake, but I sure love working with my 7900s. Funnest and most productive saws I've ever run.
One thing I will say about vibration levels (not directed at your post) is that there are thresholds. I am as concerned (and physically bothered by) excessive vibration levels as about anyone I know, but the reality is that at a certain level with good technique and really sharp chains vibration levels are not as critical. In other words, less vibration is always better, but below a certain level it becomes less of an advantage. (Diminishing returns kind of thing....)
As an illustration, my 066 (and the 460's I run) have more vibration than my body likes and I pay for it with extended cutting. But my 7900s or say my 395 (smoothest saw I own) are smooth enough that I have no problems whatsoever with extended cutting as long as I don't act stupid.
So I do believe that the 390 is smoother yet, (as was the 441 I tried once), which is of course a good thing. But since the vibration levels of my 7900 and 395 are low enough not to be a problem, even lower vibration levels alone are not enough to entice me to buy a saw.
Now lower vibration levels and more and broader power...now we are talking! I have high hopes for the 9900, and hope they kept the vibes down while making a real beast. Let's see, what was the original topic?...