The Independent newspaper publishes a top ten of various household/garden items every week.
Here's the verdict on can openers last summer:
http://www.independent.co.uk/life-style ... on=gallery

Incidentally, the John Lewis gadget at no.7 looks similar to the Culinare Lift Off mentioned previously.
Latter also deals with square tins (just about) and can be stored in a drawer to reduce worktop clutter.

Good luck with the research.

Thanks Sam.