Wayland, I cannot comment on the "other" make, as I have never handled or seen one in the flesh. What I do know is that the true Kelly Kettle is a well made item that simply lasts and lasts. I bought my original model about 15 years ago, and it's still going strong. It's provided welcome brews for countless fishing trips, shooting days and general "playing in the woods" days.No leaks. No problems. The whole concept of the thing is so simple that there is nothing to go wrong other than a seam going (which I've personally never heard of happening) or the kettle becoming damaged by being squashed or dented beyond use, and lets face it, you can break just about anything if you try, so I cannot see the "other" make being any more resilient than the true Kelly Kettle.
From my own experience with the original 2 1/2 pint model, I would say that you can order with confidence.
Edit to add that I am definitely in on the deal for at least 2 of the 1 Pint kettles if all goes to plan.
Mine is an original Kelly kettle - although dented from Camel Trophy service, and furred up inside from hard water, it is completely serviceable and doesn't leak. The base that holds the fire is a bit bent and distorted. The cork and chain needed replacing but kelly Kettle provided spares at trivial cost.