Cannot comment on MP side, as like i say in my original post, i'm purely a SP campain Halo person.Bungie done very good over the years, but had started to believe they were these great story tellers (they were'nt), so had hoped new set of designers would take the Halo franchise into new realms.
Bit of a Halo geek, bought the novels, artbooks, animationed series etc.
Reviews i've read and comments friends have said, in a good few places it feels very similar to previous Halo games and likes of Rogue Squadron.I will be buying to try for myself, just not had that pre-order urge i had with Reach.
I've always been a big advocate of the idea of playing Halo co-op and that's mainly because my friend and I have always loved working together on Halo campaigns since we first got the original xbox in 2002. co-op campaign is sooo much fun but SP is good too obviously!
Seriously though I am surprised that you seem to WANT Halo 4 to be VASTLY different to previous games, if anything I'm glad as hell that they managed to stay so close to the formula while still putting their stamp on it and improving it immensely.
Despite the setting and story of the first 3, the universe never felt that massive and rich (in the games at least, the books and other related canon are incredible!) now though in 4 the game really gets a new lease of life and it just seems HUGE!! I mean the whole point of Spartan Ops is that your on the Ship Infinity which is LOADED with spartans and you have to watch "Forward Unto Dawn" to get the history of a character in Halo 4 as well, its fantastc, to me at least, and I can't wait to play more!
Hope you enjoy it when you get it mate 
Ultrapro on xbox live
Watched the 1st 3 eps of Forward...not bad!.
Yes, i do want Halo 4 to be something different, just as i do:Killzone, Uncharted and any other franchise that's had a fair crack at the same old formula.
Been playing Skyrim, now i loved Oblivion+Shivering Isles, Fallout 3+all the DLC, completed all those and Skyrim just feels over familar.Hence my 'concerns' over Halo 4.
I'm always keen to see what new studios do with existing franchises and would prefer to see someone pushing the ideas envelope just a tad further.
Friend who bought Halo 4 on Friday been PM'ing me daily full of praise for the SP campain though, so (my) confidence is high i'll enjoy it.
So, finally started on Halo 4.
Have to say from a technical viewpoint, gob smacked by what developers have squeezed out of the 360, visually must be maxing out the hardware, audio (in the main) superb, love the A.rifle chatter etc, not so keen on new Warthog engine whine though.
Good as music is, missing Bungie's musical score, but not that much of a biggie.
Few levels in, feels solid enough, familar, but you can 'tell' it's been done by someone else, it looks like Halo, acts like Halo, but it's like a duplicate of, somewhat.
Hard to really describe so far, i'm missing the chatter from the grunts etc, but just something about the firefights that feels..'off' compared to the Halo i know.
I finished the campaign and to me it just feels like what Halo could've been but never was before, I was soo chuffed with it because the Covenant before had always just felt like a faceless, pointless bunch of cannon fodder. glad you like it so far!
Ultrapro on xbox live
Yeah, been getting back into gaming in a way i have'nt for a long time, Halo 4 was always on my 'too play' list.
So far, very solid, have noticed a few things with the A.I mind, i'm playing on Heroic, as i always do when starting a new Halo game, 95% of the time it's spot on, but had a few occ.now with the Elites just not reacting as i'd expect, if at all, to being hit.
1st few times, Covenant sniper rifle, 1st Elite did'nt react at all (i was shooting from max range) so just went down after numerous shots, 2nd and 3rd times they did react, but just slowly inched away.
4th incident, firing on an Elite from a shade turret, again, long range, again, no reaction.
Only happened these few times so far, but guess by maxing out the visuals, something had to be cropped back.
We should arrange a game night?
defo! I'd love to do some more spartan ops as I haven't got far in that, we could co-op those or mp? add me you guys if you wanna play, Ultrapro obviously 
Ultrapro on xbox live
Will add you on my main account now.
sweet! LOVE Halo 4
Ultrapro on xbox live
MVG had two lobbies of Spartan Ops, be good to bring you in more on the modern side.