J.T.
All of the Leap devices I have bought my children have not lasted past 2 years. I have bought the Quantum Pad, Leapster, and My First Leap. The cartriges can be expensive ($20-$30 each) and hard to find.
I don't know your budget, but I would go with a tablet computer of some kind- you will get more out of it and it will last much longer.
JMHO