Well, I study infectious diseases (including COVID-19) for a living, and I got my second dose of the Pfizer vaccine on Friday. My wife and one son have had their first doses, and my other son gets his first dose on Thursday. I think these vaccines have been a literal answer to prayer: very safe, more effective than we could have hoped for, and available far sooner than I thought they'd be.
Is it absolutely certain that there will be no long-term effects from them? No -- we can't be absolutely certain about anything like that. What we do know is that there is no plausible biological mechanism for the vaccines to have harmful effects that wouldn't be worse with the virus, no hint of any long-term effects so far, and no precedent with any other virus for anything really weird to happen. Since the only realistic alternative is being infected with a virus that we know is killing millions, is doing long-term damage to many millions more, and is far more likely to have weird long-term effects than the vaccines, the choice seems completely clear to me.