He's awkward and a nerd, trying REALLY hard to be a badass like the stories he heard of Vader. You can tell the upper members of the First Order see him as a sniveling shit who hasn't been shot out of an airlock because of his powers. Remember when Luke got away at the end of ESB and every single person on the bridge is dead silent and frozen in place? Vader did nothing and he still has that effect. Kylo doesn't command that level of fear and respect.
Yeah, General Hux not only talked shit to him, but he and Ren both reported to Snoke at the same time as equals, unlike Vader being above everyone (except Tarkin but that was before they'd really figured out Vader's role in Star Wars). He's definitely set up to make you think he's a Darth Vader clone, but then it's revealed he's in-universe a Darth Vader wannabe and everyone knows it.