Al Noor is just a teensy bit more westernized. It’s cleaner, the curries are less, oily, etc. But it’s still legit Indian/Pakistani food.
Al Watan is a little grubbier and arguably a teensy bit more authentic. It’s the place to go for tandoori chicken, kebabs, etc. They use mesquite IIRC. I also like their chicken tikka masala, but it comes with a slick of oil on top that some find unappetizing. Here’s a pic:
BTW, if you go to Al Watan, try the buttered seasame naan: