I've got a ported 681, and they are one heck of a saw. Actually more saw than most will ever need, but that seems to have nothing to do with what we own.
Romeo & I did a side by side comparison between a stock (broke in) 7900, and the brand new stock 681 (actually it's very first cuts), same bar & chain in (if I remember right) a 21" log. The Solo out cut the Dolmar by almost a second a cut pretty consistantly. That's not that big a deal when you're out in the woods bucking logs, but it is braggin' rights.
If Solo were to go belly up, it wouldn't be because they don't have one of the best saws on the market today.
Andy