It's a good debate of the pros and cons I'm finding interesting to read too.
I've come to a sort of analogy:
I own my house, but it would be cheaper to live in a shared flat.
I don't wake up every morning and think 'I would have to live another 50 years to make those mortgage repayments economical', so I don't really question owning my house.
The problem I've had looking for shares are pretty simple:
You need the aircraft you want available locally (or relocate/travel) - if you like club life, it would be better at your club field than some isolated strip somewhere.
You need to 'fit' in the share group (not always as simple as it sounds)
Many spam can group aircraft **I've seen** are in worse condition than the aircraft I hire - this doesn't inspire one much to the commitment of the group members.
For a group share to make any sense at all over rental there is some 'minimum' hours you have to fly each year. As rental planes usually have an associated maintenance organisation, they are actually quite competitive so it can be difficult to get the numbers to come out in a group share unless you fly an awful lot.
In all I kind of like the idea of coming home to my own house rather than a shared flat where my dinner has been eaten by a flat mate. I think I would also quite like to open a hangar door and see my own aircraft.
There is the option of course of buying and then offering shares yourself if the financial burden is too much, at least then you have some control over who the other group members are and how things are run.
So that leaves me with, if you can find the right share for you go for it, if you can't, jump in and buy it. We all have time I'm sure to become wise afterwards
I've been looking around for 3 years and yet to find a group I was prepared to invest in, though doing a tailwheel conversion opened up a lot more inexpensive options for me, it's not really what you are looking for.