Good question. For me it’s the language barrier. I’m not as fluent in English as in my mother tongue. Also there’s this feeling of urgency and importance. If I feel I have to say something I just tweet it. If I want to know what’s up – bam, there it is.
But at the end I believe it’s a brutal propaganda tool. Everyone uses it to fight for their beliefs. And because of the 280 signs limit and the immidiate responses, it’s hard to distance yourself emotionally.
On the other hand you reach less people here. If a mod doesn’t like your opinion and bans you, it has more impact on your reach than a block from a single person. Also the voting system pushes the common sense, which can be stressful for innovators and forward thinking people.
In less troubled times, when I feel more free to follow my hobbies, I prefer Reddit, though. It’s more relaxed and more entertaining.