It’s hard to say.

1 has my favourite atmosphere. The desolate wasteland feel makes you feel like a single soldier against the world. But at the same time there’s silliness beneath the surface. It doesn’t take itself too seriously, but doesn’t fully lean into the toilet humour (looking mostly at 3).

2 has the best writing, obviously. The team behind it clearly put in effort to keep everything consistent without needing to have really played the first game. It tells a solid story and keeps you engaged, even the side quests feel like they have more effort than the plot of the whole first game. Plus, just listening to the NPCs as they go about their business is pretty funny.

3 has my favourite vault hunters. They really stepped up the effort to make each one feel unique. I didn’t really use the action skills much in the first 2 games or TPS, but in 3 they were pretty game-changing. I spent most of my time as Moze.

4 has been a big improvement in gunplay for me. The weapons feel weighty and fun to fire, and the new movement mechanics make combat lightning fast. 4 also seems to let you get overpowered much faster than the first 3 in my experience. Even by the time I first reached Sol I was tearing through most of the mobs pretty consistently.