I have jammed both alone and with others. I think I've come to slightly enjoy working alone more for the creative freedom it offers, plus I don't have to worry about disappointing anyone. That being said, seeing the project advance by leaps and bounds while you're not even looking, and incorporating the best ideas from others, that's all incredibly motivating.
I'm on the lookout for new collaboraters . I've only got 1-3 hours a day to devote to game development, but if there's weeklong jam or something you want to fiddle on together, I'll drop a DM on your Discord so you can keep in touch.