been boxing with hunters since legion started it all depends what you wanna do
hunters have alot more burst damage but warlocks had it alot easyer on my experience.

example

pve
on 5 bm hunters i could burst some bosses down on M+10 before certain mechanics kicked in but i had alot of problems keeping pets alive and heal myself
on 5 affli boss fights lastest a bit longer but there pets where alot better and tanky vs hunter pets and warlock healing was out of the roof they barely dropped in health

wpvp was a bit different

hunters burst but there survival was total zero
warlocks there damage was insane and they had so much survival felt like you had a extra toon healing them

according to patch notes 7.2.5 vs 7.3 didnt really change alot for both classes so its your own choice to go