....
I can't of course comment on the RS one, but not even trying something
after buying seems strange.

I did try it, by working the tool in my hand many times, that was
enough. The operation of the left and right jaws weren't right,
sometimes when you let the tool close the blades wouldn't be open so
you couldn't put the wires in. The handles didn't move smoothly, they
wanted to wobble all over instead of moving in an arc. Sometimes it
would get stuck open.

As soon as I opened the package of the US made one, I could tell just
by the feel of it that it was a much much better tool.