As the fact I'm using an electric chainsaw probably suggests, I'm not totally comfortable with using chainsaws; I won't take one up a ladder for example (even before my much more experienced neighbor sliced a tenon with his).  So, I'm hardly an expert.  So, in preparation for Sandy, I took a reciprocating saw up a ladder to knock off  the top ~40' of dead tree before cutting it up into manageable bits with the chainsaw. With the new Oregon blade it was like a hot knife cutting through melted butter compared with the reciprocating saw which was more like trying to push a bread knife through hard cheese (don't know what's with the flowery metaphors---I made the twenty words long ago).  Heartily recommended.