When comparing speed, you should take a look at average sector length as well. The straight wing and higher thrust-to-weight ratio of the XL will allow it to get up to cruising levels quicker, allowing bigger part of the flight in cruise. We once compared H800XPC against the XLS for various sectors and found the XLS was faster on sectors up to about 1:20 hrs and up to about 2 hrs, the difference was small.
Another plus for the XL(S) is the baggage compartment. Don't have the facts at hand, but I was told it's about 30% bigger than that of the Lear.
Erik