I have both the small, Sebenza and the slim, Synergy. The workmanship on both is superb, with no visible flaws.
I agree with the posts about Jim O'Young being a great guy to do business with and he will get you the Synergy as quick as possible. And he will answer questions PROMPTLY, which means a lot to me.
I think that the best looking of the two is the Synergy and it feels better in the hand. I have not used the Synergy long enough to compare it with the Sebenza yet.
Both are great knives, I initially intended to carry the Sebenza one week and the Speed-tech the next...I never did think I would find a folder that had a lock-up as strong as the Sebenza, but the Speed-tech lock-up is every bit as strong IMHO, perhaps even stronger!
Right now, I can't say which one I prefer, but I'm leaning toward the Speed tech!!