Both are known for being bad. But which genre is worse?

Movie adaptations are way worse. There are some decent licensed / tie-in games pretty much every generation (Batman on NES, Aladdin on SNES / Genesis, Goldeneye on N64, Riddick on Xbox, Spiderman on PS2, the Batman Arkham games just to name a few).

There's pretty much zero movies based on video games that were both critically acclaimed and successful.

Edit:  Unless you want to count the Pokemon films, some of those were actually successful and pretty decent.  As were the first Resident Evil and Mortal Kombat films, but even those are a stretch.

Movie Tie Ins, the last good one I played was Aladdin on Sega Genesis, but Movie adaptions of video games are also pretty bad most of the time

So Capcom made a game out of a movie out of a game? 

Anyone?

Movie Tie Ins... They're just fucking awful.

Hmmm, a very close one in my books but id say movie adaptions. I feel its like how generally people dislike comic book movies since they arent faithful to the comics. While video games of movies at least have other elements as well as more story to it.

Although your reasoning is a good one, the Batman Arkham games are not movie games, they are comic book games.

On topic, film adaptions of games are worse. Don't think there's been a good one yet many of these games have oscar worthy narratives.

Movie Adaptions of Video Games. Seriously, tell me when a movie adaption of a Video Game is as influential as Goldeneye 007. There are good movie tie-in games you know.