The one with maxed out heroic challenges from SA and Giants has....
+3 speed
+5 armour
+3 crit
+6 elemental power
I believe this is the same increases SF had also. It's not much , but an extra 3 crit is always nice

Hopefully they've fixed the issue where any new characters in Giants couldnt get this boost coz they couldn't complete 5 or the challenges that were exclusively in SA. I'll need to hero up one of the Giants to find out .
UPDATE
Heroics also transfer over for Giants characters ! You do not have to have all 50 heroics to get a stat boost .I was testing if tree Rex got the heroic boost too and it appears that for every 5 heroic challenges you get in a stat , An extra stat point goes up in superchargers.
I haven't complete all the challenges with him yet so I'm not sure if the full forty 45 add up to the same as the 50 that SA characters can get yet.

darkspyro
net