before answering please read.
I'm going to buy my younger brother a gift. He's not much into Battlefield or other sim-similar/semi-realistic games, also he fancied playing MW2 what leads me to statement he will love MW3 or BOII.
Thing is, I haven't played in any games for a while and really have no clue which of them is better or what features posses.
Lemme be more specific:
He will play on PC: Core 2 Duo E7200 @2.53Ghz, GTX260 (800Mb, or sth like that), 4GB RAM, Win7 64 bit in 1366×768 (16:9). Is this PC going to run fluently at 30+Fps in native resolution and let's say lowest details both of them?
Is any of this game technically unstable?
I've read about some Premium etc. so:
Which of this games have any platform (I guess, it's ELITE?) that allows to have 100% access to the multiplayer options?
Is it free?
If not- is it necessary to buy such account to play in MP?
Players with Premium have great advantage or not?
Summing up premium things- in which game multiplayer thing is solved the best?
Are there any free DLC to any of this games that contain maps or he'll have to pay for this?
The last but not the least

Thanks for help n advance.
PS: Ppl who've played on PS3/X360 are also welcome to share their opinion about the games.