In most of the cases you will probably not buy timeshares from a developer, rather you will try to buy it from a middleman, agent or from the resale market. There are some pros and cons of buying a time share from a developer.
The major competitor to developers is the resale market. Resale market will give you many options. It is a common fact in the timeshare market that the cost of development is mostly recovered by the developers from the first buyer. The average price of a timeshare for a first time buyer is almost two times the cost of development, whereas the resale value of a timeshare is generally 50% or less. So from cost perspective it makes all the more sense to buy a timeshare from resale market than directly from timeshare developers.
However, the owners may not give you all kinds of flexibility that developers can give you in a deal as developers are mostly the owners of land and property whereas resale market owners are not. Also, the big developers can give you flexibility in terms of points system, floating weeks and a choice of many resorts for your vacation which a small resale market owner can not give.
It is recommended that if you are cost conscious then resale market or small owners are the place where you should look for. Else if you look for variety and flexibility in timeshare property then developers are the right choice.