I have been (and am) a single founder and also have been a co-founder in the past. From my perspective the positives of having a co-founder include the motivat

I have been (and am) a single founder and also have been a co-founder in the past. From my perspective the positives of having a co-founder include the motivation at the early stages, when there's just a couple of you. Tasks can be handed off easily, based on skill-set and it can help to accelerate the start-up. In my own experience, the negatives can be a vision/goal that is different to what you thought it was at the start (despite a lot of talking about it) and also sometimes the partners (ie girlfriends/wives) can have a direct impact on relationships. Its also easier I think to start with a co-founder as you feel you have someone to 'share' decisions with, though in my experience this can sometimes slow down decisions. As a single founder you make a decision quickly and move on. Now that I've had a few businesses over the last 15 years I much prefer to be a single founder. I hire in the talent that I don't have and this means that I can be more agile with what I do. There is NO right or wrong answer here. It's whatever is the best fit for you as a person and for the business.