Epic Lvl 60 Nick Snowball Shot Lvl 5
Holy Hymn Lvl 6 Vitality Lvl 6
HP: 10739 ATK: 802
Rare Lvl 50 Bolt Blaster Explosive Shot Lvl 5
Holy Hymn Lvl 10 Vitality Lvl 7
HP: 6929 ATK: 904
A lot depends on what you aim to do and what your struggles are. It also matter what other hero's you have.
Typically though Bolt is one of the best as his Primary skill gets very high, but Nick's snowball will do a lot of damage when its up to level 15+ (as in take out 3-4 structures big)