I've run through 700 energy in refreshes. Got 7 drops (14 shards) of Gar, 6 drops (12 shards) of DK, 6 drops of DN (12 shards). And 1 drop (2 shards) of Chirrut since I did 3 light side.
I did 98 total sims. 95 Darkside (note that 11 of these were 16 energy instead of 12), 3 lightside.
I got 20 drops total. That's a drop rate of about 21%.
Shipments produce shards at about 80 crystals per shard (320/4=80).
I refreshed 6 times for a total of 50+50+100+100+200+200 = 700.
Total shards I earned was 40 (2 per drop) : 700 / 40 = 17.5 crystals per shard, or about 25% less than a shipment.
If you want to use the logic, but I only what character X shards and I get to choose from shipments, the return is a little worse. For example, DN, it would be 700 / 12 = 58.3 crystals per shard. That is still a better return than shipments.
Obviously, this is predicated that you get a return around the 21% rate. My last run of energy I got 0 bonus shards.
I'll leave it up to others if they feel this is worth the reward. In my experience today, the return was worth it from a pure crystals/shard aspect. However, my opinion would've been different had I gotten all Gar shards, for example, instead of getting DN ones.