In terms of discounts, Matilda is more likely to have them over Aladdin. I feel like Aladdin would be better because it really does grasp your attention and when James Monroe is on stage as the Genie it's hard to not be enchanted by his charms (I also find Adam Jacobs and Courtney Reed as Aladdin and Jasmine respectfully charming, too). Matilda is wonderful and does have a whimsy to it, as well. It is a very smartly written show that works for both adults and kids. It's really your call, but I'm just throwing out my two cents because no matter which of the two you choose you're in for a fun evening.
"Anybody that goes to the theater, I think we’re all misfits, so we ended up on stage or in the audience.” --- Patti LuPone.