OK, it has arrived, and I have opened one tin of sliced carrots and one can of bitter lemon, so I can now pose as an expert.
I liked this tool.
It works on a different principal to most tin-openers. Instead of turning it round and round to cut, you move the handle back and forwards. It takes far less effort than usual, and doesn't hurt arthritic hands. It doesn't cut into the metal, it unfolds the bit of the side that is bent over the edge of the top circle, leaving edges that are not sharp. You then use the little metal clippers sticking out of the side to remove the top. Your fingers, and the tin-opener, don't have to touch the top at all, so the opener stays clean and just needs a quick wipe.
You do have to start it off in the right position, or it doesn't grip the tin, but once you get the hang of it, it is easy. It is slower than the usual round-and-round action, but takes less hand-power. You need to note where on the tin you start, and stop once you have gone right round - it doesn't come loose at that point like a conventonal opener so that you are aware that you are finished, so you could keep going for ever. Rinsing out the tin before putting it into the recycling is much safer than with the usual razor-sharp edges.
On the side is a little beak for inserting into a ring-pull and levering it off (my main reason for choosing this, though having bought it I appreciate the tin-opener function, too). I had a bit of a problem working out exactly which angle to insert it at, but once I worked that out, it was simple to use and accomplished the task without much effort.
Hope this is useful.