I've been beta testing it for months. I was having a pretty good time with it. A couple weeks ago, they re-leveled all the classes, and it stopped being any fun for me.
Up until that point, I was getting annoyed at how unavoidable getting killed by snipers was. Now, they have a policy that there should be no one-shot-one-kills in the game, but it seemed like half the time you got sniped, you couldn't get to cover fast enough to avoid the second shot and death. Now that they changed the classes, you WON'T get to cover in time. After you get to middling level (say, 12 - 15), you're going to be playing on servers that have snipers who have several points in "piercing shot," and who have bought the "quick" sniper rifle, and you're going to die in two shots as quick as you can say "bang bang."
I went to the forums to complain about the issue, and the thread got to be several pages long, but I never saw a response to any of the gameplay changes from the devs. If they would have just published their compiled stats, it may have made some sense. But without that, I can't understand it. It seemed that half the people playing Nationals already WERE commandos. They didn't need any more incentive for that.
In the process of actually IMPROVING the sniper, they made the soldier's "grenade spam" almost useless. Yes, I played a soldier almost exclusively, but that didn't bother me as much as the sniper issue. The forums were LIT UP about the GS issue.
Other issues, as have already been brought up: SLOW. You really have to take your time to get used to how slow the game moves. PACKS. You MUST work as a group to really succeed, and it happens JUST as rarely as in other Battlefield games. :-(
Tanks take, like 3 or 4 GOOD shots to kill someone (more like 5 or 6), but can be blown up with just 2 TNT packs. Heck they even take about 4 shots to kill another tank! Person-to-person, you can be killed in about a second, so tanks wind up being... strange.
Planes are almost useless. I hate BF2's planes, because someone who's really good with them can rule the whole server, and there's nothing you can do about it. Don't worry about that in BFH! They're just a big, fat target for small arms fire, which can bring them down in seconds.
One issue no one talks about, but I know everyone is annoyed by: SPAWN POINTS. You can't choose where you spawn. I realize that this is intentional, and I understand this mechanic to keep the action hot at "the line." But when you're working on an award, sometimes you need to spawn at certain points. Maybe that's home base, to get a tank; maybe that's near the center, to capture a flag. The way the game runs (SLOW!), you could spend HALF the time in the level running back to home base to get a vehicle.
Finally, cheaters. Because of the speed and size of the levels in this game, cheaters are even more annoying in BFH than other online games. You just can't get away from them. Maybe PunkBuster is fixing this, but I doubt it. It doesn't keep cheaters out of any other game I play with it! And I see post after post about problems with it. (I know it's been hassling me since I gave up on BFH and tried to play BF2. I keep getting kicked out with some sort of "file corruption" problem. Thanks, guys!) When I get on a server (in any game I play) that has an obvious hacker, I just go somewhere else. There's plenty of options. Well, in BFH, you can't choose your server, and I've gotten dumped back into the same server after leaving. That's doubly annoying.