We use a 660 with a 30" bar. It performs well but it would be good to have more power for the wider boards. And yes, the saw is useful sometimes when not planking as well.
Our oiler is set to max and it would be good to have a higher flow. I think there was a version specifically for milling which had higher flow but wasn't available in this country when we bought. A quick look at the 661 manual suggests that it might have an easier to adjust flow rate, which could go higher as they talk about it possibly running out. Ours has never been close to empty for a full tank of fuel.
It looks as though the 661 has the same m-tronic system as our 261s. Hopefully they don't cut out as often as the 261. One downside to them is that if they need adjustment you have to take them to the dealer rather than being able to do it yourself.
You don't automatically need an aux oiler - just depends on what you're milling and how wide it is. We experimented by making one out of an old drink bottle, some tubing and a tap from a water butt and it appeared to help on wide oak slabs. It wasn't an obvious enough advantage that we bought the proper oiler when ours broke so we don't use one now.
It's also a good idea to have several chains with you whilst working. We have 3 and swap them over rather than sharpening whilst out in the wood. Our original one came with the bar and is filed for ripping. Our new ones came from
http://www.northernarbsupplies.co.uk/582-rotatech-chain-loops at much less cost. They're still not sharpened to ripping angle but will be brought towards that each time we sharpen. They seem to get good reviews on ArbTalk
Never used the Husky saw saw can't compare.
Finally, if you're new to this then have a read of
this book. It's expensive but if you're lucky you can find a pdf version online...
