If I already had all the shards needed for a matrix cube and was broke when I hit 50, then I would probably use a cube until I could buy the DG relics. But personally, those shards can be a real pain in the ***** and I would rather spend the 11k. .
I thought they were easy to get. My sawbones was a real breeze, now on my sentinel the belsavis shard was a pain unless you set there and wait for someone else to do it. I know when I got mine there was 3 people setting there waiting for someone to do it so they could just pick it up.
I however, got all the datacrons on my main, so I would have gotten them no matter what.
Cunning Martix Cube Red Red Red = 54 Endurance, 80 Cunning, 8 Critical Rating add a augment to that and I did not replace it until dread guard came out.