In my personal opinion - Dark Zone experience is fine. Too damn easy in fact.
First of all - some numbers. I have played the beta since 30 mins after it went up, over the weekend, and clocked in about 26 hours of gameplay in total, 13 hours of it was one long session on Saturday. It took me about 4 hours to get familiar with the UI, the controls, to play around with graphical settings to get to solid 60fps, to explore the PVE area, get the medical wing upgrade and run Hospital on Hard mode non-stop till I got to lvl 8. At which point I went into Dark Zone, and thats where I was roaming for the rest of the beta.
Most of my play time, I roamed solo - because my friends suck at getting beta keys are not interested in The Division much. I am also not a part of any gaming community at the moment, because too many of those I've been in had too much drama, and I don't like drama, so I mostly play solo these days.
I have grouped 2, maybe 3 times. Every time, the group mates were idiots who didn't know how the game works, how to use ammo/food. Would commonly fail at trigger discipline, failing to stop firing when non-hostiles were in their line of fire, flagging the whole fireteam. So, as far as grouping with random goes - I either had bad luck, or its a really bad idea to group up with randoms in this game. I guess its a little bit of both.
Anyway - in the beginning, I found DZ a bit tricky, took me 2-3 hours to learn the layout of the map. To learn the PVP mechanics. Once I got the hang of it, the experience was quite good. In fact, most of the complaints that deal with PVP system, and balance/loot issues in Dark Zone, are written, in my honest opinion, by people who are just bad at videogames in general, and with videogames that have non-consensual open PVP in particuclar.
Just to prove that I am not talking out of my ass - this is how my gear looks as of today, when I stopped playing beta. As you can see - 2 "yellow" guns, rest of slots are "purple". I have 11 more purple guns, of varied types, that I just bought at DZ vendors to dick around with. I still have 5440 DZ currency that I have no idea how to spend.
I have tried the rogue exploit only once - that is the one where you go rogue, then go out of beta bounds to get teleported into safehouse and wait out your timer. Just to see what its like, and how it works. Rest of my gear and currency were earned through honest gameplay.
Now, I don't consider myself a casual player, but I am not a hardcore either. Not anymore. My past gaming experience is mostly MMORPG and single player action/FPS/TPS games. I never really played PVP FPS/TPS online games before. I have played EVE Online, which is regarded as the hardest and most complex PVP MMORPG ever created, so there is that.
Overall - the game in general, and Dark Zones in particular, needs tons of work. There are bugs, glitches, issues. There are some areas that are easily campable, and I think they need additional acess points to it, to make them harder to defend. There is lack of any anti-cheat system at the moment. The UI is glitchy, and the are some performance issues. Maybe some minor tweaks to rogue system - timers, some sort of permanent "security status" system, that will allow players to see how often someone goes rogue.
But from the game design point - the game is solid.
EDIT : I did went out of bounds a few times when not rogue, to get free fast travel to the safehouse.