I’m in this exact situation now and have been for many years, while previously in a gigantic company…

Pros:

You (hopefully) tend to have significantly more influence on the tech stack and software direction. 

You're (hopefully) treated like a real person and not a cog in the corporate machine.

You (hopefully) get to learn and do a larger variety of things.

Cons:

Pay can be lower, and getting raises can be harder when you're talking directly to the CEO/Owner and it is quite literally coming out of his or her pocket.

Taking leave tends to be harder when there is so few people to pick up the slack.