i regularly review products i order from amazon, and i read the reviews, as i did for this product. i was very happy that i bought it. i used it to haul two large suitcases around northern italy for a month, and am i ever glad that i had it. a few comments:
i don't think it can be used with luggage that has 4 wheels, one in each corner, as the suitcases would probably twirl around. that is, it would seem to be designed for two-wheeled in-line luggage.
the strap can slip a little to the side on the 2nd piece, so centering is important. don't know how this problem could be solved, but aside from the occasional 'slip', where i only had to re-position the 2nd of the two suitcases, it wasn't a big deal.
and i don't know how well this device would work with cheaply made luggage. the increase in weight pulled along by the one extended handle could result in a problem. i know the handle of the larger of my two suitcases was pulling close to 200 lbs. it held up, but i also sometimes held my breath.
it worked for me. hope it works for you.