I love this thing. Wavered on purchasing it for a few weeks after receiving my Micro MAP panel, but then started spending more time in the kit on long rucks and sits. I can't speak highly enough about the SAPI. It surprisingly does not bulk out the Micro Map when full, so you're able to keep a very slim profile (I'm using the K-Zero). I've never consumed an entire 3 liters in one ruck or training session, but it's comforting to know that I've got surplus hydration for others if necessary. If you're on the fence about the SAPI, just pull the trigger and get it. Money well spent.