For years, I've had 2 mtbs.
One hardtail (it's been singlespeed and geared and 2 different frames) with an 80mm air fork and fairly light bits. I've used it on the rockiest & longest of natural trails, at trail centres, UK mountains, Les Arcs and anything else you can think of. It's taken a pounding, is good fun and demonstrates that you can have fun on a cheap and cheerful machine. The current frame being Ex-Binners!
The other bike has been a chunkier hardtail / full-susser at various times. Currently in fully coil-sprung, full-suss, chunky-upright-all-day-all-mountain-heavy-enough-to-keep-you-honest-on-the-ups spec. Its been ridden on many of exactly the same trails as the hardtail. This bike is more forgiving on technical trails.
When I decide to ride I choose which bike I want to ride based upon:
where I'm going,
who I'm going with
what I feel like
which bike is working
eg. For bimbling around a flat forest I don't see any need for a big, full susser, no point having to wait for hours at the bottom of every descent or being very slow on every up.
Choose your battle and choose your weapon.