I bought one of these little saws about two months ago. I already own three other 10.8 tools, one Idrive, and two impactors. The drills will never take the load of their bigger cousins but for their size and weight I love them for tighter spaces. As to the saw, yes it has limited operating life under heavy use. I have used it on three jobs removing drywall where I did not want to use a sawzaw or roto zip do to dust constraints. On high this tool eats the batteries. I found that it is not necessary to operate on high for all uses. If I did have to operate at full power, because of my multiple 10.8 tools I have battery redundency.
If you don't already own other tools on this platform then my advice would be to not buy this tool as a stand alone piece. If like this battery platform, as I do, then yes this piece is very usefull.