It's basically the same thing as the regular XLs. Very slightly better, but not by much. If you can afford to drop $13 on a set of strings then go for it. They are definitely the best strings in existence. However, they're not more than twice as good as the regular XLs like the price might suggest.
Do you love the feel of strings that have been broken in? Well these strings give you that exact feeling and break in as soon as you put them on + they are pretty damn hard to snap!