Niinistö said at the start of the war that "the mask has been taken off, revealing only the face of war", and I think it describes the situation perfectly. Largest reason we've stayed out of NATO was based on the trust we've naively placed on having good relations with Russia to provide security. Any trust by any party on Russia is now, of course, obliterated.

To my knowledge, joining NATO does not change much else than giving us the article 5. It'll likely invite a lot of nastiness from Russia, but removing the now obvious existential threat should be more than worth it. The baltic states were right. I don't want Finland to be in this position ever again.

Seeing what Russia has done recently based on a sketchy premise tells enough how it doesn't provide us security.