I still have my Mama Bear. It works reasonably well, but it wasn't the transformative sound that appeared in the promo video (from the promo, I thought it could totally change one guitar into another). It is more like filters to try and twist the guitar into another EQ profile. I don't know if L. R. Baggs or Fishman do better these days at transforming acoustic sounds or not. (I don't have any of their gear.)
As far as pickups, the one thing I need would be a pickup that can flip from A2 to A5 on a switch. I tried two ways myself, starting with an A2 pickup and creating a filter with an LRC setup to flatten or scoop the A2 mid-peak into an A5 profile; and I tried the reverse with a peak filter on an A5 to give it a chimy A2-like peak. Would like to find a way to have all that on a single pickup, if possible. Instead of splitting, it flips the peak.
Another thing that would be useful is a pickup that somehow uses an electro-magnet that is only a magnet when switched on, and when not selected, is just a coil with no magnet; which could be used as a dummy/noise-cancelling coil or just inert, no influence on the strings or circuit. (I have no idea if this is even possible, but just an idea the struck me I could have used many times.)