So, I've spent a decent amount of time with the game, here's my initial impressions:
At first I agreed with PJ, it felt like CoD 4. Now I think it's halfway between it and MW2. That's not a bad thing, but I still don't think the whole playing experience is nearly as refined as CoD 4 was (but that's in an entirely different league than any other game I've played). The game plays more like MW2 but has much less crap to make you rage. In several hours of game time I've only been killed by a noob tube twice and have yet to be quick scoped. Spawn points aren't awful but they're not perfect. By that I mean once or twice I ran into someone 2-4 seconds after spawning, but in my mind that's still pretty quick. Knifing may be my biggest issue but it's unchanged from any other CoD game. I still don't see how you can survive me shooting you in the head with my .308 caliber rifle only to knife me...guns should trump knives when said knifer is being shot.
The maps may be my biggest gripe. It seems that every single map is essentially a ring with a few routes through it and the goal is to run in circles flanking nonstop. They definitely lack the flow of the CoD 4 maps and may not be as good as the MW2 maps. Several of them I just plain don't like (here's lookin' at you Seatown), but that's an early judgement so maybe they'll grow on me. My favorite thus far has got to be Dome which is sad because in my 40 or so games I've played it's only popped up a single time. It's like the anti-Nuketown.
Weapons feel pretty good, not quite as laser-beam-esque as MW2. My concern is that I think that assault rifles absolutely dominate right now. I've seen a few guys with UMP45's, almost no one with MP5's, and no one with LMGs. LMGs have way too much recoil, I used the MG36 for one spawn and switched. I haven't unlocked the Kick proficiency on any of them yet so maybe that makes a difference, but I can't really think of a reason to choose one over an assault rifle. I found that the CM901 (most kick of any assault rifle I used) to be my favorite weapon, especially after unlocking the reduced recoil proficiency. I don't think it's the "best" rifle, but it's the most fun to use in my opinion. I'm not sure I like the unlock order though. In MW2 you start with the M4 which is great, it isn't until lvl 48 that you get the "replacement" ACR. In MW3 you get the SCAR-L very early and honestly it handles neigh identically to the M4.
Strike Packages definitely add an interesting twist. I don't think the assault package will be used as much as Support, but after playing with all three I think they're actually pretty balanced. The very first offensive killstreak I unlocked (when I was using a default class) was the Reaper. Essentially you are in a UAV and fire down laser-guided rockets for 30 or so seconds. I know I was brand new but MAN, it is freaking hard to get kills. Maybe it's just that weak or maybe my aim was off but I think I got one kill in 30 seconds of the onslaught. I will say that the attack chopper is now one of the better rewards (at least of those I saw). It doesn't do damage at the rate of a Harrier but much more than the chopper did in MW2. With Support I got an Osprey Airdrop once but the match ended before I got to use it. Lots of UAV's, enhanced UAV's, SAM turrets, and Ballistic Vests, and the little gem known as the Support Drone. If you are the kind of player who has trouble getting points this is the killstreak for you (and it's VERY handy for the team). Fly a little chopper and "tag" enemies. When they are tagged they show up on everyone's radar until they die AND they receive a minor flashbang effect. You get points equivilent to a kill for everyone you tag and you get an assist bonus if they are killed. On one TDM game I had nearly 20 tags, that's 2000 points with almost no effort.
I've used the Specialist class quite a bit, it's actually kind of neat. Set Hardline as your #2 perk and you get three bonus perks at 1, 3, and 5 kills and another at 7. This makes getting Hardline Pro easy...really easy.
The differing strike packages work well and will definitely appeal to different players.
I'm not sure I like the weapon sounds, they all seem to be pretty grating, guess that's a minor gripe though.
You level up pretty quickly, at the end of the night with no double XP I was sitting around lvl 23, I'm up to lvl 41 now.
Oh, and Elite is downright broken right now. Couldn't even use the app last night, the website is down, etc. Glad to see my $50 was money well spent.
Honestly if you're a fan of the series you'll like this, if you're not you'll find nothing new or groundbreaking here. Personally, while it'll never be a CoD 4 level game, I think it's the next best in the series.
Stupid question - how many weapon proficiency's can be active at once?
Only one.
I haven't been playing yet (thanks work) but if you can play MW3 online then they are not equal. BF3 servers were a complete pile of crap almost the first week. Lucky for EA I like BF3 and was willing to suffer through that because when it worked it was fun.
I don't care if elite works well as long as I can play.
I've had zero connection issues thus far (well, except with Elite but, as you mentioned, who cares).