You could really ask this question of anyone about anything. There will always be substantial differences between one person's life and another. Having had children doesn't necessarily denote that difference, even less so for men as some fathers don't stick around and instead go live their own lives seemingly uninterrupted.
But think of how many things people sink great amounts of time and effort into; gambling, becoming a practicing doctor, hedge fund trading, starting a charity, programming... Those people will probably all have large amounts of time devoted to those things.
Of course there'll be many things that don't compare, and some that do... Then you must also factor in that it's a trauma for some people. Some people end up not liking their children, kicking them out, disconnecting.
Human nature is hugely variable. What's it like being a good person? What's it like being rich? What's it like being homeless and a drug addict? What's ut like being happy? What's it like in prison? What's it like as mayor? Or psychiatrist? Or teacher?
What's it like not like doing any of the things mentioned here? Well, that question, your post, is really about you, isn't it? It's about you asking others "what would my life be if I didn't, or don't have kids?"
So, why are you asking?