Hi dgolds!
I've got a Tumi briefcase that I've carried everywhere for about ten years. It's been great, except for one problem. The springs in the clips on the shoulder straps gave way and the shoulder strap started coming off. Tumi has a lifetime warranty against defect and they called this a wear problem. The cost for a new strap was about $40 (but the new strap is actually much nicer.)
I've found the stitching and zipper action flawless so am surprised that you luggage gace up in four years. Based on their overall performance, when I started travelling frequently last year I bought a Tumi overnighter.
It has worked well so far. Crammed full, it still squeezes through UA's scanner templates. My one complaint about it is endemic to the style. It is a softside piece and is a bit difficult to pack until I get enough things in it for it to hold its shape and stand up.
I also have some Samsonite hardsiders that my father gave to me a few years ago, but that I haven't used that much due to its size. The largest case has built in wheels and a handle. On a recent trip through the Belly of the Beast one of the wheels broke off. That did not make me happy, since I've only used it a few times. I've not yet checked with Samsonite about repair.