Show Xpress costs more then MyDMX. Show Xpress costs along the lines of Compu Live, which much more powerful then MyDMX. Apples to apples. Unless you count the dumb down 100.
As for more then one universe, more handy then you give it credit for. I have lights on the right side of the room and lights on the left, control setup in the middle. Send one universe to the left, one to the right instead of having to run a massive DMX loop around the whole room, costing more time and more money. Also remember DMX can only control 32 fixtures on one universe which can be useful to do now-a-days since it seems everything is DMX controllable now. Two universes can be a blessing real quick.