Banshee has better action scenes than Strike Back but Strike Back has better gun porn. Banshee also has better cinematography, tits, and Antony Starr who can emote so damn well with just the shape of his face and his ass is divinity and can turn any straight man gay.
That said, Season 2 of Banshee has been a bit too melodramatic. The producer said every episode would be "50% better than any Season 1 episode" and that's been mostly not true. Also kind of overindulging in the "shots within shots" thing where he intercuts characters doing things in-between them doing other things, such as a character being stoic then the character flailing around in rage for a couple seconds then back to stoicism to emphasize a character's feelings. Or intercutting a character in introspective reflection with something they'll do 10 minutes later.
Banshee S2 kinda feels like Cinematographer's Experiment Session a lot of the time. It doesn't work every time.