I picked up my copy of Black Ops the afternoon it came out (didn't want to be a part of the midnight mess) and have logged about 20 hours or so of multi-player game play in the past week. That has given me a chance to get a pretty good feel for the pros and cons of the games So with that, here they are;
1) Environment Visuals - If you have not seen the game in 1080p, you should. On a large screen (I have a 42") the environment is gorgeous, and very photo realistic. One of the things I did not like about Modern Warfare 2 was the "cartoonish" look of the scenery. A good thing that Treyarch needs to run with every time.
2) Difficulty - It was SO frustrating to start off initially with the game restricted to core with only the M16, a shotgun or a mule-kick LMG. This was very similar to World at War and I like it! MW2 was a very good pick up and play game. The M4 started off as my primary weapon from level 1 and it never changed. With that, there was no learning curve. This game had plenty of it.
3) ONLY Gun Kills for Killstreaks - This makes care packages worth the time. No more Predator, Harrier, Chopper Gunner combos.
4) Scavenger doesn't pick up equipment - No more Double coverage for snipers/campers. A big plus.
1) SPAWN ENGINE! - Countless complaints have emerged about this one. This to me is a MAJOR downgrade from WaW and MW2. Did it suck that you might respawn across the map from the enemies because of an AFK/camper? Yes, but it is much better than spawning 3-5 times in the middle of multiple enemies, or getting in a Spawn loop
2) Particle Effects - For items like dust, moths, and sparks, these items look rushed. Dirt in the air looks like an over-zoomed pixel in MS Paint. It looks like the deadline was coming and this was totally overlooked.
3) Enemy Footsteps - I'm an old school Counter Strike player. Footsteps in that game were amazing. You could tell the location and number of enemies through a wall with good headphones. MW2 and WaW you could at least hear one coming, but were unsure where from. In Black Ops, enemy footsteps have been silenced so much that what is the point? This makes the Ghost perk VERY powerful. At least in WaW and MW2 you had Dead Silence/Camouflage and Cold-Blooded/Ninja Pro that took up 2 perks. Stealth became a class in itself.
4) Massive Maps - Like World at War the maps are massive with lots of places to hide/maneuver. Unfortunately this can cause game play to get ridiculously slow (esp. in Hardcore) and encourages camping. MW2 had Derail, Estate,and Wasteland. Black Ops has Array, Crisis, Grid, and Jungle. Radiation isn't on the list but I would consider it a major camping map.
So there you have it. Overall the game is good, and with some quick patching it can be great.