Is this the first time you are thinking about buying any of these two vehicles? I think buying them would be one of your bigger mistakes.
Jeep Wrangler is not a very good vehicle. It is a gas-guzzler and it doesn't ride very well. The suspension is so stiff! You will just be bouncing inside the cabin.
The Grand Cherokee is a little more sophisticated. However, the vehicle is also a gas-guzzler. It may look nice on the outside but the reliability is very bad.
I suggest get a Hyundai Santa Fe instead. Or if you want an American vehicle, get a Ford.