Convert or be a Noahide?

The recent thread here about Noahides got me thinking about this:

Let’s say a gentile comes to the conclusion that Judaism is the right religion. How would they decide whether to convert to Judaism or to be a Noahide? Being a Noahide seems like the better option to me, since that person would still have fulfilled their duty in the eyes of G-d, but would have fewer responsibilities. Despite this, however, it seems that converting to Judaism is more common than becoming a Noahide.