Good things about XNT:
1. The battles are much more violent with lots of bullets and explosions, and armor is much stronger, which means your troops can get into shoot-outs with the aliens without getting one shotted usually. It's fun.
2. The alien AI seems to be a lot smarter.
3. I like the new enemies, especially the xenomorphs, I don't think they're overpowered, although the Omega and the other big ones should be delayed until the later game.
4. The new tech is very cool, particularly napalm grenades.
Bad things about XNT:
1. Writing of Xenopedia very bad!
2. A lot of the new tech has no pictures. A lot of the new guns have no stats telling what they do and how they're different. It would be neat to give each xenomorph its own lab dissection picture.
3. New guns should not replace lasers, but be a stepping stone towards them. Lasers should be better and required. Maybe increase the armor of later enemies to make lasers required, or make the later enemies resist ballistic. Also maybe instead of requiring the manufacture of new guns just replace the first guns with the new ones automatically as they're discovered. Also don't make more than one new ballistic gun, just replace the pistol with a new pistol, the rifle with a new rifle, the sniper with a new sniper etc no need for two new ballistic shotguns, three new ballistic pistols...
4. Stats of xcom soldiers are weird. TUs have no upper limit? Strenght is capped at 82? Not sure...
Overall though I like XNT more than vanilla and hope it gets polished, I can help with editing xenopedia