The 3000 micro is nowhere near the SB2000 Pro, and they’re more expensive. Also one SB2000 is going to take up less space than 2 micros. So the only advantage I can see here is the dual sub aspect.Not sure if this is a serious question or not ?
But quite often consideration has to be given to WAF or aesthetics, generally 2 subs are going to be better than a single sub, better coverage over more of the seating areas and a smoother response too. Also it might not be possible to accommodate dual SB2000 Pro's or at least not in the best positions, whereas dual 3000 Micros might be perfect.
According to what has been reported about the 3000 Micro, it's a very competent sub for it's diminutive size.