The pain you felt is most likly from one batch having a higher b/a contant then the other. This shouldn't make your gains more. Maybe one was underdosed. Either way there both great stuff. Think I would go with ethenate. It should maintain a higher ave. test level. With sust your levels go up and down. I love sust but the guys on one of my other boards are all for ethenate. Never used TT stuff before.