I used to live in a block where the leaseholders exercised their right to manage. Unfortunately, the only leaseholders who had the time and energy to get involved with the running of the block were a handful of awful buy-to-let landlords who each owned multiple flats in the block. They went too far the other way and let the block fall into complete disrepair, and then had a major falling out with each other. While it was fun watching the fireworks (they really were a bunch of greedy, pompous ****heads), I’d vote against self-management if I ever ended up in that situation again.