ExOfficio Air Strip Lite shirt.

I use their Geotrekr. I think its just the short sleeve version. White button down shirts are the way to go.

The only problem I have with it is that it's way baggy. I had to get a medium because the arm's on the small weren't long enough.

I sent mine back pretty soon after I got it. The fit was all wrong for me…way too baggy in the torso area and the sleeves were too short… That was a bummer too because I really wanted to like the shirt.

If it fits you though and you like it, I would say it would be a reliable shirt for a thru hike. Pretty much all of the reviews I had read on the shirt before/after I bought mine seemed to be good (which is why I ordered it). And after handling it, the shirt seemed to be well constructed, like it would stand up to some hard use. Just my opinion though.

EDIT: I see that you posted while I was typing my response. I see that you have the same experience with it too…

As baggy as mine was on me there was no way that I would go up another size. The sleeves may have suited me better on a larger size, but then the torso would have definitely swallowed me whole… I think a medium with the XL sleeves might be a good fit for me, and I really don't have long arms…

I like it. I got mine last season and have put it to some use. Compared to Cap 2, the airstrip isn't as breezy but better in direct sun IMO. The fabric is thin and light and will absorb a bit of sweat to help cool you off some. I think the baggy fit is a good thing for hot weather as more air gets circulated as you move. The sun protection is excellent, I didn't get burnt at all. Hmm, what else. Oh, I did find its not 100% skeeter proof. I got a couple of bites around my shoulders where the fabric was draped close to my skin, but it was just a few. I'll say 97% skeeter resistant lol. One more thing, it dries fast. I washed it at 6pm and hung it up overnight. It was bone dry in the morning.

P.S. Not as smelly as cap 2 after a few days either.

I have one. I actually wear it 3 seasons, but in summer I make sure to bring a camp shirt to change in to. If you sweat like I do on the trail, you will understand. But for me at least, any shirt is going to be like that, so I like this shirt because it is light, comfortable, and dries fast.