A tinted front attaches over your optical frame, usually magnetically or with a small hook at the rim, and comes off when you go back indoors. One prescription, two uses.

No. A clip is cut for the front it was made for, so it has to match the frame — not just the size but the shape of the rim. Buy the pair together.

It is cheaper and it travels as one item. A dedicated prescription sunglass looks better and sits better. Which matters more depends on how often you switch.

That the clip covers the full lens with no gap at the outer edge, and that it holds when you look down. A clip that shifts is more annoying than carrying a second pair.