Buying any business is risky. Nothing is a guaranteed success. There are some franchises that you need to take a little extra caution with. This doesn't mean that you should avoid these all together just that you need to take a little extra care to make you know exactly what you are getting into. 
Getting in early on a franchise definitely has its benefits but you have to be careful. Early on the systems and supports have not been fully tested. 
Buying a re-sell can be a cost effective way of getting into a franchise but you need to make sure you really research and find out why they are selling early.
Both these situation can be amazing or complete disasters. Luckily with a little extra due diligence on your part can help you make a smart decision.
Happy Franchising!