Which is the best when dealing with Sigma, Tau, Theta? Could you please place them in least to greatest order.

Thanks.

I believe they have numbers in the icons that show you, or at least the multi-tool ones do.

..I guess theta comes first of those in the alphabet. But it's sigma->tau->theta in the game (..why not epsilon or chi last instead? We'll never know. There's also omega gear - got one blueprint, still haven't seen the ingredients on the list). This title rank is independent of the number on the upgrade, I think, that.. maybe(?) increases whenever you pick up a second blueprint copy?

So presumably the weak and cheap variants tend to become more powerful more quickly. And you get bonuses from putting similar systems next to each other. So new systems don't obsolete the previous ones completely.

Haven't been able to figure it out yet, but think maybe the additive bonus depends on the highest ranked item (or that maybe the number on the upgrade is the additive bonus?) in the chain. And that it's not completely linear. Since adding a third cheap/sigma shield to connect to the main module (adding two "adjacent" bonuses next to a theta shield) seemed to count for more than adding a tau shield somewhere else, for example.

So instead of hurting for titanium all the time, to save up for the expensive shield later, you could be better off by sacrificing that titanium slot for a chained cheap shield module. Sort of suspect that the chain works in all directions as well, so you might get a higher bonus by having a square of the same category gear than just having them connected in a line. In the sense that if you add a beam cooler and a beam impact chained to two other beam upgrades, both damage and cooldown increases more than if you chained them in blocks of two elsewhere, or just a line downwards. Or, just guessing, that if you put a high ranked (+number) item in the middle of a tetris block, the additive bonus affects each system at the sides, but not the ones at 45 degrees out. Or that in a square, you only get bonuses from the gear connected at straight angles. Still, adding that extra item on an angle away from the main system still pays off more than adding it disconnected from the other systems.

It's also possible that there's some threshold values involved that make theta+sigma gear chained always hit over some fictional "limit". So that if you were, say, adding a theta warp reactor that wasn't chained to the main warp drive, you can make up for the lack of "max jump needed to get to blue stars" by adding a second warp-reactor in the chain.

It's a bit mysterious how it works, and no one seems to really know for sure yet. But at least adding a cheap shield in the middle to connect a high-level upgrade to the main cannon or shield definitely pays off more than just building a mid-level shield somewhere else. So those additive bonuses are high.