As an avid fan of both The CW’s DC TV series ( known as the ‘Arrowverse’ after the oldest of the shows, Arrow, but which also contains The Flash, Legends of Tomorrow, and Supergirl) and Netflix’s Marvel Universe (Daredevil, Jessica Jones, Luke Cage), I have compared the two fairly often, trying to figure out which one I prefer. Here are just some of my thoughts on the matter.
The most obvious difference in the universes is the tone of the shows. The Netflix/Marvel shows are dark and bloody, while the Arrowverse is much lighter and generally more comedic, which allows the Arrowverse to feel more consistent to the storylines found in the source comics. This in turn gives the DC shows a wider appeal, satisfying the dreams of die-hard comic book fans and also younger audiences and families looking for the fantastical.
For example, the Marvel shows are mostly about superheroes in New York becoming heroes hiding their powers to protect themselves from government surveillance in the wake of the first Avengers. Meanwhile the Arrowverse has plot lines about people who have straight-up magic powers. While the Speed Force (how Barry–the Flash–gets his powers) is made an actual God-like being, the most fantasy-esque aspect of the shows is that people generally don’t hate superheroes (or, more often, vigilantes) just because they have powers.
One of the main things to consider is that the DC TV series is on primetime and has limits on its violent content while Netflix shows can be much darker and deal with more serious themes. This leads to truly terrifying villains, from the unbridled rage of Daredevil’s Wilson Fisk, to the psychological terror that is Jessica Jones’s Kilgrave. The Netflix shows also have an ability to humanize their villains in a way that attaches the audience to them despite their obviously psychotic actions, most memorably Fisk beating a man to death with a car door–to the extent where his head explodes. Kilgrave is especially terrifying, as much of his storyline is about rape culture and consent, as he has the ability to control minds and doesn’t seem to find anything wrong with sleeping with women while they are under his control.
The Arrowverse, on the other hand, is not only family friendly, but also timely wraps up the villain's storyline at the end of every episode and/or season arc. The audience has little to learn about the details of a character’s history, with the exception of the (usually mostly hidden) villain of the season.
This definitely works in Netflix’s favor; the Arrowverse villains never feel like much of a real threat. No matter how often the villain beats the hero, we always know that the hero will win somehow. While the same is true in the Netflix verse, it feels as though the stakes are higher and the villains are more dangerous. This has been credited to the realistic nature of the characters, who aren’t wildly overpowered to beat the equally overpowered hero. This is most obvious with the villain of season 4 of Arrow, Damien Dahrk, who has mostly-unexplained magic powers which are somehow telekinetic and have the ability to kill someone by touching them, but only in specific circumstances. The Flash has a similar fault in that the villains of both of the seasons so far have had the same powers as Barry, but stronger.
Another comparison to be made is on the format of the shows. The DC shows are single 40-45 minute episodes every week for 20-22 episodes. Marvel shows are 13 hour-long episodes that are all released in one go, so the Arrowverse must have big events in order to keep the audience interested, most often in the form of crossovers. While characters from one show appear in the others on a semi-regular basis (and some actors even have contracts across all of them), there is usually a big crossover between the shows in late November-early December. This is not needed in the Marvel/Netflix universe, as the shows don’t need to keep the audience tuned in over nine months. That said, the shows do have characters crossing over–namely Claire Temple, who has appeared in at least one episode of each of the series so far, among others.
Between the light-hearted Arrowverse or the adult-orientated Netflix/Marvel universe, there is no definitive decision on which is better. My preference honestly depends on what mood I’m in and whether I want gritty hard drama, or something a whole lot lighter.