I have enjoyed the COD series, but gave up on Black Ops after a bit - it just wasn't any fun. I was getting butchered all the time. Whether or not people cheat isn't clear to me. It may simply be that a 12 year old boy raised on FPS's can kick my 52 yo butt with ease.
I missed the game play though, so took on MW3. The single player is fine. Lots of scenarios and fun ops. Not terribly hard on normal settings. Multiplayer has so many games that I haven't touched, but I enjoy Dominion and Kill Confirmed. I like Barebones, which is still present. Somehow I tend to do better there. My issue with the game is that it disenfranchises the marginal player. You enter a match with your Sergeant's stripes and everyone else has Prestiged a couple of times around. You are really fresh meat. There is just not much that a sucky player can engage in without invoking the wrath of little punk brats, dragging down your team, or just feeling like you spend more time dead than alive, all of which seriously diminishes the fun of the game. It would be nice to have some stratification of talent, and advance through a grouping of more similar talents and expertise rather than just throwing us all in together. Or have casual rooms to play in.
If you are in the same boat, what helped me a lot was finding a clan. They do help coach me, tolerate me, and make for just a good time rather than a harrowing experience.
I do think that the online service has improved. I don't get dropped nearly as much. There is occasionally some lag, but not often enough to matter. You occasionally respawn right in the middle of the other team's presence, but this is sort of funny - you gotta laugh at getting pummeled soundly at some point.