Depends more on the perks than the Hand Cannon itself in regards to Legendaries. As far as Exotics go I only have TLW and Thorn, and they are way too different to really compare.
TLW is unmatched in close-quarters hip-fire scenarios, and will be best utilized by "high-risk high-reward" players.
Thorn has significantly more range and accuracy and combined with the poison-effect for keeping shields down, offers more tactical options. Much longer reload than TLW, almost requires Hunter with Chain of Woe or a reload speed boost from gauntlets.
As far as Legendaries go, I like Timur's Lash for sheer damage, reforged it for Crowd Control and Flared Magwell, but Red Hand is great with the perks it dropped with.
Reactive Reload (damage boost after reload after kill) and Outlaw (headshots increase reload speed) is [b]one of[/b] the best combinations for a Hand Cannon in my opinion. Especially as a Gunslinger Hunter.