I couldn't comment on Dive Caddy since we don't have them here in my country, but i agree with what meesier said, Force fin doesn't age, and the reason for that is because Bob simply made his Fins with the highest quality material available, thus extra manufacturing cost, but 1 pair of Force fins is all you need,...it doesn't break, it never changes shape, and will continue to work fine 30-40 years from now...It's a great investment...or should i say 1 time only investment in fins...
i always calculate the TCO (Total cost of Ownership) while purchasing my dive equipments, means that i calculate how long i want to use the equipment, maintenance, durability, scalability, and resale value, and in my opinion Force fin fit to those criteria, except for resale value, i'll never sell my Force fins! and Yes it might hurt a bit, might need to save up some more to buy the fins, but all you get is a high quality product that really works, and can last like forever (in diving time).
The difference between Pro and Normal Force fin is in material they used. Force fin pro is stiffer and have more snaps/rebound compared to the originals..So you don't have to be a Pro to wear Force Fin pro,..