If anyone watched YaYa Toure today in the FA semi easily steal that soft clearing pass and then see him pitter patter his way to the goal - well, that is what I see constantly happen against me when I play online because of lag. Perhaps most frustrating is that when I experience lag my opponent is not; so how do you compete with that?
I spent way too much time today exploring the problem and repeatedly find references on every site, including pesgaming, on the problems with lag. I found the same problems posted with FIFA 11 but only the 2011 installment of the series. FIFA released a patch that doesn't seem to help but it is obvious evidence that companies realize there are problems outside of our hardware and connection speeds. I think connection speed adds to any problem (10mbps down, 2 up is one, but only one part of my problems). Plenty of old references to Konami frantically releasing fixes to online lag problems with PES 2008. Again, more evidence that software issues exist.
In some ways, I don't know how it is even remotely possible to connect someone in the US and someone in Brazil and not expect Peer 2 Peer split second synch mishaps. Maybe I should not be expecting anything but problems - Type in any of your favorite game titles into google and add "online lag" after it and you can be overwhelmed with hits. But as Ricky posts above, he hasn't experienced the type of lag in other games and probably with games that have hundreds of thousands more simultaneous online players. So it circles back to very real software problems or server problems. I have had a few non lag games and they were fabulous so we know it is possible just too inconsistent.