I am a size 6 in pants and bought a small and they are still too large (I am also 5'11"). Also, the drop in the crotch area is very low and the rise is pretty high on the waist. Could just be that they don't fit my body type, though.

I hike alot and mosquitoes love me (and I get horrible welts) - these pants have definitely helped in keeping the pesky bugs away (it's not just because they are pants, 'skeeters will go through fabric when it is stretched). I'm 5'9", usually have trouble with length but the longs work. Overall they run a bit large so if borderline and/or between sizes go down. Very comfortable - only thing extra I could ask for would be a large side cargo pocket.

I'm so glad I bought these pants. They fit perfectly and comfortably. My intention was to only be using them for one or two days but they were so perfect and versatile that I alternated between them and another pair of Ex Officio convertibles all week. I was on a cruise and used the lavatory sink to wash them out. It's amazing how fast they dried. They were worn with some long silk underwear at the top or Irazu volcano where it was cold and rainy and through the hot and humid rainforests. I wore the shorts over my swimsuit but didn't even bother to take them off for a refreshing dip at a swimming hole in Corcovada. They dried on my body in no time. The "Buzz Off" feature never came into use since there was no insect problem during my trip.