Once you've unlocked Xanion...

[Altissimus]

...what do you use it for? Isn't Trinium better overall in every area, once you take into account the weight saving?

[Ohm is Futile]

Better performance for technological blocks, such as shields, generators, hyperspace cores, computers and such.

 

It also has more HP, depends what you're trying to achieve with your ship design.

[DerpSuper++]

As Ohm has mentioned, it has better performance for technolohical blocks (gyros, shields, generators, batteries, hyperspace, CPU blocks, etc.). Furthermore, despite being ~30% heavier than trinium, it is still lighter than titanium and is considerably more durable, roughly 50% more going by this --->

 

However, it does not possess armor blocks, used to protect against railguns, and Trinium is still better for blocks that do not scale with material due to its lighter weight. My advice would be to build a ship that mixes both Trinium and Xanion, or at least that's my approach to it.

 

As an additional note, some might use Ogonite, but I personally don't except for weapon mounts as the weight is a huge turn-off for me.