i use the GYM Buddy and have since it came out. That app in my eyes is the best hands down. However, if u need pics of how to workout then it isnt for u, but if u know what exercises look like then yes GYM BUDDY ALL THE WAY !!! it's like the walmart roll-back guy on STEROIDS!!
I use the calculator on mine a lot. And the picture and video function. I also use my iPhone to hold down my training notebook. Seems to work well for me.
JEFIT just came out for the Iphone today. I have been using it on android for awhile, but it just means I have been having to keep my old android phone around. This programs is AWESOME, which I combine with myfittness pal for tracking my intake.