These crystals look fairly amazing overall for those of us who enjoy melee rogue. Obviously some things are unfinished or bugged, as they show a bonus of +0 but we can still extrapolate some data.
A poster on the forum said he tested and the MM bonus is 10% energy reduction and the BD bonus is 1% per stack up to 20 stacks, and it self-refreshes.
This makes the BD crystal the best one by far, especially considering every raiding spec right now uses BD. The 4 piece bonus is junk, but thats fine.
The Nightblade crystal will be extremely awesome for PvP. I'm not sure if their will be a way to get multiple synergy crystals, but if so, running 4 piece R2 in PvP as Nightblade will rock, with 30% bigger Blazing Strikes and 15 stacks of Scourge of Darkness. Pretty awesome right there.
The Saboteur 4 piece bonus looks very good as well, but unless they nerf Sabdancer, the BD crystal will be better. I'm not sure why Trion keeps putting Frag bomb bonuses on Sab things. Frag bomb is garbage for everything. Very strange.