I know wracking one's brain over the near infinite possibilities in combat decisions this game presents at any one second is insanely inefficient, but I can't help but feel like any time such a deeply rooted game mechanic is discussed versus another a lot of factors get left out or looked over because it's easier to look at it cut and dry.
Like burst vs sustain for instance.
When it comes to these two, sustain is most effective when you can shoot (and hit) a target until you finish them off. It doesn't make much sense to try and boost and dodge around when your target is outmatched and in the open. Even if you can evade your opponent shots all day, it's not in the person's best interest to dance around so much when the objective is to defeat your opponent. You have dps and range options as well as a lower risk of getting caught where you can't escape assuming you utilize the distance your optimal range gives you.
Burst should be played to its full effect differently though. Generally sporting much less dps, many burst mechs don't have the option to stand their ground like an assault can vs an opponent (if they want to survive that is). Heck, just getting that preemptive strike off on your opponent as a burst wielding mech can help even the playing field when severely out dps'd. Burst doesn't always have the range option sustain has either. Sometimes you HAVE to play sneaky to be able to do anything in a match aside from just yolo diving every time you respawn. Something with a sustain weapon can just find a nice lane or peek their head over a rise and peck at the opponents and be feet from a safe angle.
There are so many more examples of things both combat mediums have going for them. There are so many gray areas too. Like hyginos said about the tech's prestige. I wouldn't classify that setup as burst, or sustain. That's a grey area caused by the mech's primary role.
Then there is the SS. Burst by definition, but the way it most effectively engages an opponent is pretty different than most burst mechs because it has so much more range. Yet, when it is put into a cqc situation, which by the way is not the optimal way to play even if it is badass; it then plays much like the other burst mechs but with a slight handicap. Another grey area.
Then there is the G2 assault. That's what I would consider a true sustain mech. But it's so fundamentally different than every other sustain mech in the PC build because of the lack of a projectile secondary. This mech has a very clear disadvantage over the other sustain mechs that have secondaries like the tow or GL when fighting on their terms. But once you get the drop on somebody and get in damage a little bit sooner than your opponent the playing field is evened out. I would argue that one of the most effective ways to engage with this mech is nearly identical to what many burst mechs benefit most from playstyle wise. Grey area.
The problem with the sustain mechs is not the sustain itself. It's the near perfect combination of burst and sustain you get in most of these "sustain" mechs. Secondaries like GL and Tow give you a way to punish a mistep on your opponent's part. Utility in not needing to aim perfectly due to splash damage or lock on, and even more utility in being able to remote detonate or bounce your shots around corners and off of objects is more valuable in combat than almost anything else. Your opponent has one more factor to worry about and take into account if they are to successfully take you on. With the burst vs sustain argument you're only getting half of the picture on one side, and I think that's precisely why reloaded made the assault standard with two vulcans. They understood the real problem with it. It does BOTH playstyles' jobs, at half the effort either of the individual, pure burst or sustain combo mechs can do.