As far as my favorite, the AR is a better design, more ergonomic, the sights are easier and quick to put on target. The maintance is a bit more than the AK, but without enough comparable maintance it will jam also.
The recent situation with the former vet from Pittsburgh who shot the 3 policeman with an AK, it jammed, thats why he stopped, that is but one of many many situations with even highly trained operators with well maintained AKs that jammed.
An AR is higher mainatance, of course, but easier to pick up, be trained on, and be deadly accurate with.
As far as the AR vrs AK74, the 5.45x39 hits with a bit more force at distances closer than 150 meters, the 5.56x45 hits with more force beyond 150 meters and continues to be better as the distance gets bigger. The Russians have complained about the switch, but some have praised the switch to the smaller round. If you look at those who like the smaller round it is the more highly trained soldiers, example, the Spetznaz. Then again typical Russian military firearm training for most soldiers is limited to a few rounds in basic training (the 2 weeks that their unit beats them up and haizes them), then around 5 rounds a year if they are lucky.
Ive never met a real soldier that complained the 5.56x45 wasnt enough, or that it couldnt do the job.
To compare you must use accurate information, the M-16 never left me down nor did it ever fail to do what it was designed to do. In combat, in training, in the swamps, in the deserts, in the snow, in the dust, or after being wet it always worked, even if I didnt keep it as well oiled as I should have a few times, or as clean as I would have liked it to be a few times.
Regardless of your personal choice its yours to make.
I remember hearing the comment that more people in this world are dead intentionally from being shot by AR/M-16s weilded by soldiers worldwide than any other single rifle. This says alot for a world with an AK falling out of every kitchen sink, and around every corner. If there were only as many AKs made as AR/M-16s the world would have a different opinion of the AK, and its effectiveness.