Are NHT VT2.4's harsh, or is it just me?

The NHT's can be harsh with the wrong equipment. Let them break in a little bit and see what happens. They're actually a fairly revealing speaker although I have personally liked the 2.5(not the 2.5i) for home theater. They have the soft dome and I find it more to my liking. Good luck.

If you want to "push" the woofer break-in, aim the speakers toward each other, wire one out of phase, turn the bass up, and let 'em pound away for a few hundred hours.
THEN listen. The tweeter will still be bright because that's what NHT's always been about, but at least you'll then be able to give them a fair hearing....
I wouldn't be surprised if you still found them a bit wanting...due to a "U"-shaped spectral response...the old west coast sound. You can modify the bass end with room placement, but the midrange will probably still be pretty sucked-out vis-s-vis the treble. Do these come with a tweeter pot or switch?

I used to listen to my 2.9's with socks between the tweeter and grill, if that tells you anything.