We've had an Ownerships share for the past 7 years after hiring for over 20 years. At £6000 plus the annual costs of around £900, it is the best thing we've done. A guarantee of 3 weeks a year plus as many others as you can fit in. If you like winter cruising, that can be quite a lot.
Yes, there is some debate on mooring sites, but it is usually a sort of North/South divide. The Southerners don't like traipsing up the M1/M6. As it is, most mooring locations are well North of the M25. For myself, living in Southampton, I am happy to go anywhere. And yes, it is a majority decision.
We have just sold our share for £3000 as we have bought our own boat, so my total costs for 7 years are £9300. I estimate we have had 26 weeks cruising. 15 years ago we were paying Alvechurch over £1000 for a week on a 6 berth boat.