What’s the difference between IPL and YAG laser? (Photo)

I suffer from sun spots/dark brown spots that I desperately have wanted gone . I originally purchased an IPL (since i’ve got it once before and loved it) when I got to my appt the lady told me I could get yag for only $20 more and said it works much faster and is more intense . i’m just wondering if IPL and YAG has much of a difference on what it does to brown spots ? and what should I apply on during the healing process ? I know I have to wear spf :)