Major differences I've noticed between this, the private beta, and TD1.
-TTK is lowered drastically, for both better and worse. Better because even Elite enemies can be taken down with gear you'll pick up along the way, better because the PVP (both Dark Zone and Conflict) feel more about skill/tactics than OP gear, worse because you can get one-shotted if you're not watching your ass.
-Movement is more fluid in the open beta than in the private by a longshot. Massive deliberately loosened movement to prevent the "chicken dancing" that was everywhere in TD1 PVP (quickly sprinting left and right at close range to become a harder target), but getting stuck in doorways and entering the wrong side of cover is an issue. This is absolutely going to be patched along the way but will be closer to what it is now than TD1.
-Gear is better balanced and builds are more diverse with the introduction of brand sets. Three pieces of D&H brand gear gives you boosts to accuracy, critical hit chance, and critical hit damage in addition to each individual piece's stats. Massive have already confirmed that gear sets will be returning later on, so I'm hesitantly excited about mixing/matching different sets to optimize my preferred build (LOVED the 7/5/3 ratio in TD1).
-Weapon mods are a mixed bag. The way of acquiring them is improved, unlocking them via perks at the BoO or crafting based off blueprints via challenges, taking the RNG factor out entirely. The downside is how ridiculous some of the plus/minus stats on them are. An angled grip that improves accuracy by 20% but diminishes stability by 10%? Top rail sights that decrease accuracy but improve crit chance? These need to be adjusted quickly, and probably will on the sooner side.
-Traversing DC is exponentially more immersive than NYC. They've taken notes from the positive feedback that the West Side Piers expansion from TD1 1.8 and made DC feel alive at nearly every turn. I have no complaints about how freeroam feels. Perfect.
-The Dark Zone will be available in three flavors at full release: normalized (what the beta has), Rogue 2.0 (current TD1 DZ), and Occupied (total free-for-all, no Rogue mechanics, higher tier NPCs). They're going to be rotated on a regular basis, so if you want to farm DZ East but want to wait until it's normalized? Give it a couple days, or however long the schedule says.
Overall, this is an improvement on the first, one where exploration is rewarded much better. Having random battles in freeroam, or even walking up on a war between a pack of Hyenas and a squad of True Sons, is exhilarating, nevermind the fact that you can follow supply teams out of settlements and help them accomplish their missions.