I would say join a group even though I own one. I still run mine as a group. It costs lots more to run than I expect even though I get bags of help from an execellent facility at Blackpool called Pool Aviation.
Contributions from other pilots helps keep the costs reasonable and I rarely find it is not available when I want it (it has happened abuout five times in six years).
If you can afford it and have the extra funds available for unexpected issues which I can assure you you can expect to happen then outright ownership is the best of course. There is nothing like leaving your plane as you want it. In mine you end up plugging in items and moving seats and tidying the plane before each flight. Also I hate the hours clocking up but then it massively helps towards the costs. I may have sold the plane by now because of the financial burden if I didnt have these contributions.