I just posted the Link Removed. Scroll all the way down. The only thing I found with the Beta 52 is that is has a very tight pattern. Just a inch can effect the amount of stuff it is getting form your bass. Good for feedback rejection but bad if you move around like I do. I might try mounting it to the back of my string afterlengths or something. We'll see. I'm reserving judgement though I have a favorite thus far.
The specifications describe a very extreme microphone, as all the high frequencies are "cut". I can't hear it very well from your clip... did you maybe notice if the sound was boomy, or too much set to low frequencies?
Concerning the "moving around" topic, I almost solved the problem, with this home-made stand, that I did.
(But that exploraudio looks more evolved...