I have both a 950 and 950XL. If I could only have one, I would probably choose the XL, but I have been enjoying the 950 as well. It fits a bit better in my hand. Unfortunately, I dropped it a couple of days ago and the screen cracked. The phone still works, but that was a bummer to say the least.
I haven't done any close side by side comparisons between the two phones. I bought them back in November during the last BOGO deal, and I had only been using the 950 for about three weeks. I didn't really much difference in terms of performance between the two, even though the XL has a faster processor. I would say that the battery life on the XL seems better.