Reviving an old thread - but came across this online. Thought it might interest some guys here...
Powersharp Chainsaw sharpener.
I bought one when I was in the US at the start of the year. I find it works well, if the chain starts getting a bit dull then strap on the sharpener and 3 seconds later you are good to go.
They are cheap over there, here, not so much.
The teeth are a bit more delicate than the standard chains and I have bent one and it led to the chain jamming in logs which was a bit annoying. It has worn down so isn't an issue any more. I think the chains are more suited to cutting American soft woods than dry Aussie ironbark, but it still goes well.
I had to hunt around to get the stuff there though (not much call for chainsaws in Arizona I suppose) and it didn't look like the idea was really taking off, so I wouldn't be surprised if this good idea withered and died. I got a new bar (you need a new bar to suit the sharpener), the sharpener and 3 chains (chains come with a new sharpening stone), so I should be good to go for a while at least.