Pero coliseum was much better than shards, you could easily get all the cards in the boxes also the items in the boxes were much better than what we get with daily wins in shards, the only downside was the ranking reward, since you would need the event cards to get it.
Osawari Island LV:96 Mobile Code: FUFB94NVST
PeroPero Seduction LV:51 SED: ~990k ID:398275
Duel Squad LV:70 (RIP)
Girls Kingdom LV:70 Castle LV:10 (Quit)
Flower Knight Girl LV:90 Power:330k ID:514096129
Dragon Providence Total LV:233 CBP:1103411