i love doing ladders. i've hit 200 pushups, 84 pull ups, 30 (assisted) pistols per leg, 25 handstand pushups, and 15 dragon flags in just over an hour using ladders. no way could i have hit those numbers just doing straight sets. i do consider myself to be in pretty good shape, and it took a while to get there, but ladders really helped me cram in some extra reps to my workouts.
but, if i had to pick a program, i'd probably go with fitness formula over ladders. that's closer to what i'm doing now, and it's a lot harder. this is all based on personal goals though. i'm pretty happy with my strength in most areas, but i feel like i need more endurance...and the larger sets in fitness formula seem to go after that more. you've got to figure out that goal part for yourself. either program would be great...and both can be used on all the exercises in primal blueprint fitness.