I played an abrupt jaunt wizard for a long time, and I can tell you: it's amazing. You can jaunt away from attackers (since it's an immediate action, you can move in response to their attack, and move so far that they cannot attack you again, since you can only move 5' during a full attack action). You can jaunt out of fireballs (if you've got the spellcraft to tell where it's targeted, a squishy DM rule), you can jaunt through walls of force. So many things you can do with this power, it's truly amazing. And since you can use it 3+INT times per day, you usually have a lot of uses for it.
If you roll poorly in defense, the best bet is to minimize the number of rolls you need to make.