I have both phones. So I pose the question to myself and answer it dead honestly................
Yes. For ME it is a yes. But not by a big margin. (I consider $120 not a big margin)
However, if someone took Continuum away from the 950XL, I'm not sure I could do it.
Not even straight up! I love that dang 1520 that much.
Keep in mind my 1520's show no wear and do not have any of the phantom touch screen issues.
(One of them does have a burnt out backlight for the back-button)
So, even without Continuum, if we were comparing a well worn 1520 for a brand new 950XL, I'd probably still make the swap.
Have I made it any easier? lol
It IS a tougher decision than folks without 1520's might believe.