Do I Need a Full Suspension Mountain Bike?

I’d say it depends what you’ll be riding mostly…

If you are looking to do long distance races (< 25 mtb miles at a time), and/or over rocky courses, and/or your technical skills/line picking ability is relatively novice then go FS ( the FSR series is solid, I ride the FSR Expert and have no complaints).

If you are looking to ride short distances, and/or go as fast as possible, and/or your mtb skilllz are dialed in then go hardtail (Specialized Stumpjumper Carbon, or an Epic pseudo FS)

Of course, FS in general is going to be more expensive than a hardtail.

In my opinion the frame itself is meaningless, its more about the quality of the shocks and the components as those are the two biggies that, if kept working properly, will keep a smile on your face (and money in your pocket!)