I have been a group member for 9 years and the main benefit has been the flexibility it gives me. I can usually fly when I want to and go wherever I want for as long as I like. If I have to wait for the early morning mist to clear, I am not usually worried about being back for the next renter's slot.
I agree that, to financially justify buying the average share, you have to do do more than about 3 hours a month. Fortunately, my misses does not like horses but she does enjoy going on cruises. As you cannot financially justify the cost of a cruise, usually a 15 day one costs enough to buy a share in an aeroplane, I have never felt the need to justify any extra cost of my type of flying, some of which she actually enjoys too.
For several years before buying a share, I used to rent a group owned aircraft and this tended to give me the best of both worlds, paying a higher hourly rate than the members but giving me similar privileges. This would be the ideal arrangement for new pilots if the insurance does not become an obstacle.
The other issue for those flying on a limited budget is that of maintaining currency. Many renters seem to have quite restrictive currency rules which mean that you have to fly little and often. Most people eventually get bored with this and tend to give up. Of course, sharing flights is an excellent way of expanding one's horizons with longer flights but then you are in danger of tripping over the 90 rule for carrying passengers. I used to have problems with this when I rented the group owned aircraft. I did enjoy some great longer flights but, during the Winter especially, did run out of the 90 day currency. I distinctly remember spending over an hour de-icing the aircraft just to spend about 15 minutes doing three circuits.
So I tend to agree with those who suggest waiting awhile before deciding on what sort of flying you really want to do and whether you can afford it, whichever route you decide to take.