The downside is that all of this enjoyment relies to an unprecedented degree on the people with whom you're playing. Bad players can screw up a typical Capture the Flag match in any other game and be booted with no lasting damage, but in MAG's persistent, interlinked warzone the failure of one squad can bring everybody down.
Getting strangers to co-operate online is a lot like herding cats, and it's notable that the only game to really succeed in this Grail quest has been Left 4 Dead, a game that scaled everything back to the bare minimum: four players on a strictly defined path. By creating open-plan environments that can accommodate any strategy, MAG also leaves the way open for those with no strategy at all. Leadership seems to be a vague concept, not helped by the PS3 community's continued aversion to voice chat.
Some of my leaders during the beta have left a bit to be desired, too. You can put yourself forward for a leadership role once you crest level 15, enabling status perks to those who stay close and calling in special support functions, but the only words I heard out of one leader all match were "sniper was bad", while another gave an inspiring pep talk about the intricacies of the map and the danger of sniper points before proceeding to, well, hurl us at the same brick-wall defences over and over. Another was more interested in talking to his friend about hot sauce and bongwater than in giving any direction to our slapdash assault.
Such complaints are true of most team-based FPS games, but where MAG differs is in its reliance on mutually beneficial performance. You can lone-wolf it, of course, and I often found more success as a solo sniper creeping around the outskirts of battles than trotting dutifully behind the pack, but that rather defeats the object. There are dozens of games like that already.
MAG needs to show that it's something more, especially since you need all targets to be captured for the battle to reach the tantalising carrot of 256-man warfare. It only takes one squad to fail for things to come undone for the whole platoon. In Sabotage, whenever I found myself on a dependable team, actually capable of taking and holding an objective, chances were that the squad tackling the other installation failed to even get close. The timer ticks down, the game ends in a loss. The sense of elation when it works is immense, but frustrating doesn't begin to cover it when it doesn't.
Extrapolate that to the full battlefield where there are 127 human variables with the potential to muck things up, before you even factor in the 128 enemies actively trying to stop you, and you begin to see the mountain that MAG is boldly attempting to conquer. But of course, this is just a beta trial, and the first few days of one at that, so there's little point trying to draw any long-term conclusions regarding player behaviour. You can form your own clan relatively early, so hopefully as more players congeal into coordinated groups these problems will dissipate.
From beta experience, that's going to be the obstacle MAG must overcome if it's to fulfill its enormous potential. Judged purely from a software point of view, there's little doubt that Zipper has come up with something quietly remarkable. There's virtually no lag even with dozens of players on one map, and the only glitch I found was an occasional hiccup where one player's prone form would suddenly start sliding around the map.
If everyone takes it seriously and performs properly, it's conceivable that MAG could revolutionise online console FPS play. But that's a big "if", and it's the community that will not only define the experience but make or break it. The task before Sony, then, is arguably not one of promotion but of education. Treat it like any other FPS launch and the result will be a damp squib. Get people in the right frame of mind, however, and MAG could be explosive.
MAG is due out exclusively for PS3 at the end of January, with retailers agreeing on the 29th ahead of an official announcement.