I have used this shirt for backpacking, climbing, and casual wear. The fabric is as you would expect from a shirt in this style; superbly comfortable, breaths well, dries quickly, and is very durable. Even after a week of warm weather backpacking the shirt picks up a little odor that is easily cleaned and will not hold on to stench as some shirts will.
The roll up sleeves are incredibly easy to use and convenient and you totally forget about it when it is either rolled up or down in the long sleeve position; the inner retaining strap and button on the sleeve cause no discomfort and are unnoticeable in regular use.
I am not certain what the other reviewer is showing on this shirt because there is no button on the retaining strap for the sleeve and the mesh backing is very well attached to the shirt and I have had no trouble putting the shirt on partially buttoned.