First, I'd like to say, good luck out on deployments and I hope you follow up your service with a good career. Take advantage of the GI Bill and having education paid for.
Secondly, get the Mini.
The Mini has a MUCH better resale value and it's a much newer device. The iPad 2 is coming up to the 2 year age mark and the Mini is still the most recent generation of what it is. Exact same hardware, only maybe 1.8" smaller.