This is going to be a great topic.
Personally i would start talking about the legends, i was a Bloodhound main but during S1 i had the chance to try out all the other legends thanks to the 25000 legends point we needed to get every week; i started using more Mirage and Octane but let's say that i use pretty much everyone depending on who the other team mates select!
Only remark is on Caustic: i like to use Gibraltar because his ultimate hit really hard and can be game changing but i can't use Caustic at all; i find him too slow (mechanically speaking), to position his traps takes ages and too often they are not enough to affect the gameplay, unelss you end up in bunker or similar and even then enemies can easily avoid them.
Now, about the weapons, my first choise was always the Spitfire over everything else but after the nerf it just lost its appeal; the flatline at the moment is my favourite one along the havoc/devotion and as a second gun i usually go with a smg (Prowler as a first choise if i manage to find a select fire orelse an R-301 over the R-99 and the 99 over the Alternator) or a shootgun (usually an EVA-8).
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