"Steve W." fired this volley in news:B_iBp.10733
:

I have used just about every saw out there. From plain circular saws
through the K-12 and our carbide toothed chain saws.
The twin does as well or better for the tasks we use it for than the
others in a lighter and easier to handle package.

What I don't understand is this:

Even with a carbide blade, running a blade backwards into the work dulls
it quickly -- it rounds over the cutting edge. With that contraption,
one blade is ALWAYS cutting backwards. Just the friction heating alone
should kill blades quickly.

LLoyd