Which is better, the iPhone 6 or the iPhone SE?

The 6 is bigger but the SE is newer and maybe more advanced, in terms of software? I don't know. What are your opinions?

Software-wise they would be the same.
Just because the SE is newer doesn't mean it would be better.
I would go for the 6.

Talking strictly specs, the SE has a somewhat more powerful processor since it's got the same chip as a 6S. It lacks some of the other features of the 6S though, like the improved fingerprint sensor and 3D Touch features.

Compared to a 6, you probably won't notice a significant difference though, so it's really more if you prefer the new thinner/larger design or the classic style of the SE.

The hardware and software of both the 6 and the SE are identical in terms of capabilities, just that the se has smaller parts due to its overall size