I don't want to say it will beat up on a 460, I haven't run one in a long time, but it does beat up on all the stock 044/440's that I've run. That being said, it doesn't quite have the resistance to stalling out the chain as say, a 461. That's ok, it's light enough to brush with and it still has enough power to easily run a 28" in stock form...mine now has enough power to run a 32", also has the HO oiler guts from a 461R, so it'll oil a 32" as well. With a good chain, it self feeds into the wood nicely.
I'd say the 500i is in a similar situation. If I can keep the chain speed up, it'll rip with a 36" in softwoods. That being said, the rev's do start to drop when you lean on it...but it's not to the point of easily stalling the chain out(my main gripe about most 70cc saws.) My ported 066, the revs don't really drop until you're at the point of wondering why you're pushing that hard on the saw. I honestly don't have much run time on my 500i yet...outside of my actual job, most of my recent cutting has been with the 400 or climbing saws.
The one caveat to the 500i, is it sounds like some had some variances in piston height, or at least that's what I've heard. Enough height to change the port timing and possibly why some people think they rip and others think they don't. Mine's a good runner, but I'm stihl curious about digging in and seeing what makes it tick...and if I can improve it.
Speaking of 500i content, tonight I was working on an upgrade for the crappy stock 462/500 clutch cover. I'm using a cheap aftermarket "west-coast style" cover(044-066). A little trimming and grinding, it fits: