I've played with it when returning to TT after my 30 year hiatus, hoping to find a semblance to the 729 rubber I used in the 80s - eggplant-coloured, very tacky, supple, well-tempered but not too slow. I still have a blade with an old sheet on it, and if I clean it it lifts the ball for a few seconds, even now, and it still plays well. As does the 30+ years old Sriver L on it, which after trying modern day Srivers that went unplayable in a few months makes me think things changed. But I digress.
Today's 729FX didn't play anything like the original 729. 729 FX/BS is a very hard rubber. The top sheet is not tacky and won't even begin to lift a ball. The blue sponge is only available with the black topsheet; in red you get an orange sponge which feels less hard. That I don't like, I like to start out with the same rubbers on both wings and then see where that leads. Not an option here.
Both are slow, and I couldn't squeeze much spin out. The red one even less so than the black one.
I don't boost; I didn't like speedgluing back then, felt the insecurity and volatility it created was detrimental to my focus. And I still don't like it now. So I can't speak about that, and it may be entirely possible that there are rituals to modify these rubbers that improve their playing quality for a little while.
There's a 729FX Super Soft, which has its merits as a beginner-level rubber. It's relatively affordable, controlled, and has sufficient grip to support all basic techniques. The regular version, not so much imho.