I bought a Big Agnes Copper Spur 1 person tent in 2010, and am happy with most of the features... except for the main door zipper in the inner part of the tent (across the mosquito netting).
In 2012, less than two years after the tent was purchased, the zipper started separating (when zipped shut) at the top. At first I was able to re-zip it, but the problem got worse and worse. I sent the tent back to BA, and the zipper was repaired (I think replaced) for free.
Last week, less than 2 years after the repair... the exact same thing started happening, so I will likely send the tent back for repair in a few days.
Is this problem familiar to you folks? The reviews don't mention it, but reviews are typically written after just a few weeks of testing. I have a BA seedhouse UL1, purchased in 2005 or 2006, and it has never has a zipper problem. I know zippers do wear out; the zipper on my TNF June Bug started separating after about 25 years of use.
I tend to think this is a design flaw; you can't set up the tent (so it holds up in a wind) without putting a lot of tension directly across the zipper. The folks from BA said the separation likely happened because I go camping/packing in dusty areas, and the dust wears out the zipper. I guess that's true, but I take the older UL1 in the same areas. In 2012, the BA folks said they would return the repaired tent with a zipper lubricant they recommended, to prevent the problem from recurring. They forgot to send such a lubricant, and I'd forgotten the exact name from our telephone conversation, so I just used some other zipper lubricant.