Has anyone who has either the Fatboy or the Jumbo (not the S version) tried them on their left side? I have been waiting on availability of the Jumbo S, but I might be heading to NOLA soon and wanted to get it for the deployment. Can the regular Jumbo be worn on the left, either by adjusting the strap or repositioning it on the person?

I just got the Jumbo a couple weeks ago. You CAN wear it on your left if you choose - I don't think it's quite as comfortable, but I don't think it's entirely uncomfortable either. Wearing it like that would put the Nalgene up front. Over all I like the Jumbo, plenty of spots to attatch more gear / bags, etc. I used to have the Thermite, the Jumbo seems to be a little more than twice as large.

I have a standard FatBoy and wear it on either side without any adjustments. I need to look at the Jumbo as I think the FatBoy is just too small for most of my needs.

I have the basic FatBoy, and am left handed so wear it on my left side. No problems for me. Quite comfortable. Just something to get used to I guess.