The petrol saw has the fastest chain speed and can be used anywhere outside, but as I move under cover into the wood store (a Dutch Barn), I prefer to use the Electric Saw which has a slower chain speed, so slightly safer. Also much quieter and pleasant to use.
You don't notice. But a sharp chain will produce chips about the size of rolled porridge oats, and a blunt chain with produce more vibration and dust.
Agree, that sharp chain should produce wood flakes, rather than dust.
But, find the small difference in chain speed, means it isn't worth using a petrol saw, when mains electricity is available. Because a petrol saw is usually 'running', even when you're not cutting,.
Battery tools are very dependant on battery life. This deteriorates: when the battery gets old; if if not used regularly; or if it's cold. So basically battery OK, if you're doing little, and often, in the warm.
My son uses battery, for certain tools, but only because he handles loads of them anyway, through working for SSE.
If you have a Dremel (or equivalent), an easy way to sharpen chains, is using a rotary sharpening stone (sized to your chain). Frequently dip it in parafin, or white spirit, for cooling.
Never had any luck with chain files.