I have Poe and Chewy at 4* and purple gear. Poe is much better in Arena play. He has much better speed so he's able to get his taunt off early enough that he'll do a better job protecting sid/lumi/etc. who are normally targets for human players in the first round. Also his expose combined with a slower AOE char (Maul/Boba/Phasma) can dent the HP pool of the enemy pretty good. Poe dies by the second round more often than not but he holds the attention of the enemy long enough for me to usually knock two of their best chars out.
Chewy is on my A team in galatic war. His taunt is effective enough in GW and he can self-heal which is much more valuable in GW. In Arena he's very easy to work around and rarely effects a battle.