If your not looking for pockets, stay with the sport skin. If you want pockets, bypass the tech skin and go to the limited edition.
If you need thicker kneepads go with the LE as its 2mm neoprene in the knees, the other 2 just have a print for knees.
Tech Skin has stretch panels for mobility made of lycra, LE is stretchier and more resilient so less pocket sag and it holds the suit tighter to your body, but you dont know due to the stretch....LE is the most comfortable in my opinion after extensive dives in all of them.
If your looking to save money though, and dont care about some of the above, stay with the sport. This suit makes all other drysuits outdated, so you cant pick a bad Fusion
Hope that helps....dont forget accessories like patch kit...not that it tears easy, but who doesnt want a patch kit just in case...its cheap and heat activated so your not without your suit for more than an hour if you somehow get a hole....best $34 alot of customers have spent(people on their knees, urchins, battered shore entries/exits, etc)