Our old patio door did the same thing the track wore out and it started dragging every time we carried anything through to the garden. We went with French doors in the end, and the sealing turned out to be the real test: the first heavy rain after fitting showed whether the installer had done it properly, and thankfully ours held up fine with no draughts since. I'd ask specifically about weatherproofing and hinge quality, not just the look. French doors is worth a look when you're comparing installers.