I signed up for Club Mahindra a year back. At the time of signing up we (me and my wife) were offered various options (white/blue/red/purple seasons plus room sizes).we evaluated all the cons first (RoI calculations/read reviews, asked family/friends etc.) and finally chose the one the option that was a right marriage of our holiday needs as well as my budget.
We were also offered a complimentary holiday which we have already availed at their Coorg property. Were were 6 people (4 adults and 2 kids) and the holiday was a thorough family experience as we could keep both the kids busy with a lot of in-resort activities. The food and beverages was also something that I will remember the holiday experience (esp. the daily special kids menu).
A lot of reviewers have complained about the inability to get bookings. With my experience I can tell you that there are 3 things I feel that are must for a guaranteed holiday booking; First is no outstanding dues on your account.
Second you should have taken a right season membership. ( Dont expect a confirmed booking for a busy season when you have a membership for a lean season)
Third is to book well in advance to avoid disappointment.
We have managed followed the above three and are going on a second holiday in Goa for the month of Feb13.
p.s. I am not a club Mahindra employee.