The VS MAX bashing is generally meant to be taken in comparison with the other MAXes and MAX counters in general. Being a user of one myself, the VS MAX isn't entirely worthless at doing what MAXes are meant to do- shoot tons of bullets while taking even more bullets to the face. If you're fighting one head-on as anything but another MAX or heavy with shield and armor certs, you're going to get chewed up. The VS MAX excels at mid-range gunfights with minimal cover, they've got two guns loaded with at least 75 rounds per magazine, so reloading and cover are very frequently necessary, and usually only required when faced with overwhelming odds and lots of explosives. In very close range they lose a bit of effectiveness due to shotguns and SMG fire against infantry. They need to put at least 6 bullets into every infantry they hope to kill, not counting heavy assaults with shields. That means every single kill requires focused aiming for several seconds which leaves plenty of time for infantry to unload whatever they want to shave off your health. This also means a single light assault with some C4 has fairly good odds of winning a fight as long as they move in an erratic pattern while in close proximity or utilize flanking and attacking from above. This all generally holds true for TR MAXes as well, with some minor differences. I haven't played one since beta though so I couldn't say what those differences are.
I've been having a lot of success recently against NC MAXes as infantry by simply getting as in their faces as possible and running an erratic circle around them. They end up missing most if not all of their shots, try to reload, and continue to miss as I shave their health down. I've actually killed a few solo even as an engineer with an assault rifle. I've come to the conclusion that most NC playing MAXes are in truth terrible at FPS games and use their one-shot cannons as a crutch. The people that are really skilled are instantly obvious with this method, I've come up against a couple people where this tactic simply doesn't work and they one-shot me without a single missed shot, multiple times. The only reason this tactic never works against the other factions is that they have too many bullets in their clips. Even if they miss half of their shots, that's still upwards of 25 bullets they've landed depending on the faction. You can adapt it into a sort of hit-and-run though, where you quickly distract them for a very short period of time and get in a few shots before turning the nearest corner/hoping off the nearest ledge etc and circling back through another route. Even if you take a few shots you'll be disengaged from their line of sight and you can let your shields fill up before going in again. If they have engineers repairing them... Well, that's just easy kills waiting for you to take them.