I like my HexBlade because he can do decent damage to single target, and if I "waste" my spellslots I can do some nifty area damage as well. And lets not forget all the movement spells which helps you move across the battleboard. And the best damage cantrip in the game Eldritch Blast makes my character do good on ranged as well, (Especially with the right feats and invocations the range of the EB is unchallenged by any class). Out of combat, with the right invocations and skills, and the high charisma, the options for roleplaying your way through the world are immense.
What it boils down to is how well you mix the feats and invocations with the spells you choose. AND the most important part of being a warlock, how strict/nice your DM is towards the short rest rule. Some tend to not give that many short rests due to the fact that most classes mainly needs long rests to "reset" their abilities, so the warlocks are almost punished if your DM doesnt follow this up and help you play your class.