Isolation is more on the bodybuilding on steroids side of the spectrum when using it alot. If your not a bodybuilder on steroids then I'd consider sticking fully on FBW and compound exercises. If your trying to be fit and strong then FBW is the way to go. You don't have to do isolation but you can put it in occasionaly in workouts if you like. Like working out M W F with a FBW you can put in a isolation exercise each workout. For example monday do 2 sets of curls, wedensday do 2 sets of tricep extenssions, and friday do 2 sets of weighted crunches. Thats for if you add isolation. It all depends on how you want to do it.