I've heard a lot of mixed reviews on the Jaco's -- I was considering picking some of these up...I'm essentially looking for a good short that will be good for both Muay Thai and No-Gi BJJ, as you said.
I've seen a lot of talk about the sizing...do you have yours one size up? I wear a 38 in jeans (and am just slightly under 6'), think a 40 would best suit me in these?