I have been involved in a couple of groups. I now own my aircraft with a very silent partner (5hrs in 12 months) and am in a group now on a pressurised tourer.
Groups are a great way of getting into aviation and allow you to keep the costs under control. The downside is often that you have to travel to get to them and you have to work around other bookings. They also allow you to get into higher performance groups for longer distance touring, all weather etc if that floats your boat.
I have a 2 mile hard runway at the end of my drive and the relief to that 2 miles away where I keep my aircraft so I am never more than a couple of minutes away from flying it allows me to fly when I want. Not having any group members to book around means that I can fly when I want and go away touring at the drop of a hat.
You really have to decide the type of flying that you want to do and decide what suits you best.