Kefuddle,
Others have answered your points better than I could but may I make a suggestion? It all depends on what kind of flying you really want to do: you may or may not have strong views. But before you buy into a syndicate I'd suggest you go out and fly as many different types of aeroplane as possible. If you can do this on the basis of rides with other PPLs that's great, but also think about going to a school with a good and varied fleet and getting checked out in a variety of types, e.g. if you trained on a PA-28, get checked out on a Cessna and vice versa. If you're into serious touring, try and get hold of a Grumman AA-5, and a Robin. If you are more into local flying and pure enjoyment of flying for its own sake try a Cub, a Stearman or Moth, etc. There are several places where you can get experience in lots of different types, at least enough to get a taste for what makes you happiest. You might be surprised at what you find most enjoyable, and then when you do make a hefty financial commitment, you won't get trapped in something which leaves you feeling a little flat six or twelve months down the line.
Also, the experience will be very good for you post-PPL, and having a few more hours, and being signed off in more types, may help to open doors in terms of the way that members of other syndicates, and their insurers, look at you.
Actually, joining the PFA might be a very good idea as some of the best-value flying around is in syndicates formed around PFA types.