I dropped my iPhone 4S the day after I purchased it - shattered the camera lens. I purchased the clear back panel and liberation kit.
The screws on the iPhone were on pretty tight so the pentalobe screwdriver that came with the liberation kit was immediately stripped - it's pretty cheap.
After I received the premium driver, all went well. The driver fit perfectly and no stripping of the driver or screws.
Definitely go with the higher end driver - save yourself the time and frustration. Well worth the money.