My impressions so far?
Not even at 3 hours yet, but I've played enough to pick up on a couple things.
Firstly, 5 years on, you'd think that Treyarch would be able to predict and plan for the opening couple days. I had to give up trying to play today after not getting into a game for 30 minutes. I tried solo, in a party, different gamemodes, different people in my party, nothing worked. Hopefully they have this stuff ironed out before the weekend. The menus and lobbies are also horribly laggy, the friends list doesn't work (keeps flying up or down 10 spots at random)
Other than that, it's been fun. The gun damage in low for Call of Duty (feels like 4-5 bullets to kill every time, rather that 2-3 in MW3) Makes the game more skill based. The connections are really good, like MW2 good. I can count on one heand the number of times I've felt cheated by connection, people die when I shoot them, and when I die it's usually my fault. The game plays very fast, I actually like the spawns, they are far more predictable than MW3.
SMGs are very powerful, I'd advise against using a silencer on them, turns them into hitmarker machines. The Assault Rifles are decent, I've used the MTAR a bit and it is a good gun, I've heard that the AN94 and the Scar are both very good. Recoil seems low on all of the guns, with a grip it's almost zero.
UAVs are everywhere, and I mean everywhere. Every game has a constant uav, right from the start untill the end. When I unlock Counter uav it's going on, also considering using Ghost when I get it. Yet to decide whether it's acceptable or not, I played against a guy who was using Ghost and rushing like mad with it and he did pretty well. It's certainly a viable rushing option. the scorestreaks are tough to get, but damn are they powerful. If you can reach the high ones they are worth 15-20 kills, but they are very rare. I've only seen two lodestars called in and a few choppers in 3 hours of play, the lightning strike is a really good streak (particularly on HQ) You don't really need lots of kills to get lots of points or to rank up, as long as you play the objective you are going to get lots of points.
Once the servers are sorted, I can see this game being a lot of fun. Smooth connections, people are moving and playing the objective, in particular objective play is rewarded greatly. The few farmers I've come across have not done well at all. It's a game that you guys and other players like us will do well on, and hopefully have fun on.
Also I have a feeling that Alpha is going to love the KSG, weird gun but if you practice with it it'll be very potent.