2 of my favorite balls for when the lanes start to dry out that definitely compliment each other.
The Melee Jab is definitely the stronger of the two and it definitely rounds the corner a lot stronger and is more responsive to surface changes (I like mine best at 3k as it is not so sharp).  If you are looking for help opening up the lane and want to maximize the help presented by the dry boards, then this is the ball for you.

Despite the marketing, the XOXO (in my hands) is a very smooth rolling ball that works well once the lanes and broken down into the medium/dry range.  I prefer this ball for when I am trying to take advantage of the hold inside and want to keep my angles a little straighter.  Its what I used in Singles at Nationals this year.