As always, it will depend on what you are facing and what the rest of your squad has.
In the current unstable TLT meta they might be good.
The Obsidian swarm is strong vs. PS2 Y-WIngs and the Gray Y-Wing will outbid those. It's all about maximizing against what you think you will be up against in a tournament (in a casual game, it doesn't matter as we are simply having to much fun doing pewpew noices).
If you can PS kill an enemy before it fires, Grays are good.