I have a Strider GB, and have handled many of the Buck versions... I thought about this as well, when I bought my Strider, it was the most expensive knife I had ever purchased, but it was well worth it... I suppose if you get to handle the exact knife you purchase, a Buck version is a good compromise... Mick and Duane would not have allowed their knife to be 'copied' if they didn't have some faith in the company producing them, I am sure.
However, have handled a few Buck/Striders, and most have pretty good lock up... But the real deal is solid as a brick S**t house. NO blade play in any direction. When compared to the real deal, ANY blade play seems like a lot of blade play.
Another difference that made me choose an original.... Notice the finger choil on the AR/GB is very pronounced... the one on the Buck is only present on the handle, not on the blade... I found that the choil really helps with more 'delicate' work with the blade, as I have more control and stability while 'choking up' on the blade.
No offense to last poster about the Al Mare SERE, but the SERE is not NEARLY as solid as the Strider... I have one as well, and love it for different reasons... Get an AR (if you can find one) or a GB... you will not regret it... and If you don't like it, you will have no problems reselling it for the same price you purchase it for.
-Dave