When replacing fence panels I always get asked which type is best and it can always be doen to budget most times.
Before you even consider panel, what type of Posts will you be using? Re-using the current fence posts or replacing them with new ones?
Concreate fence post with guide channels for panels will be the quickest and secure ones to go for, but may not be under budget.
Wooden fence posts rot in time and may not be as solid as concrete ones and so as well as picking the right fencing contractors you also need to pick the right timber or post products.