My hardtail was my favorite bike I've owned. Fast, flickable and so fun to jump/drop/etc...funner than the Bullit. Having said that, I wouldn't go anywhere near Porc. with an HT. Yes, it can easily be done and Yes it'd be loads of fun, but Moab beats the shit out of you, even on a big bike. Lots of rock fins, stutter bumps and baby heads.
I also have nothing against going up, but you can do that on an FS just fine.