Pros
Pay was good relative to cost of living. Housing was good was taken care of by HR. The work place provided a safe and supportive environment to foreign teachers. It's great place to learn and grow, and for foreigners Urumqi is a really good place to get out of your comfort zone. It's a lot about what you are willing to put into it. If you are willing to make some effort to learn basic Chinese, go to parks and talk to people, go check out some places that aren't listed on the map, then you will have an amazing experience. I had an amazing time there and that was because I spent a lot of time looking for new places to go to in my off time and spending time learning about the culture.
Cons
Very few foreigners in the city and security checks can be a hassle. Big culture shock and difficult to adapt if you aren't willing to put the time in to learn. Many teachers struggle because they expect to arrive and be treated like royalty. This is not the way it works though and this leaves many teachers to be demoralized very early on. In EF Urumqi you need to put the time in, both in work and outside of work. I learned this after 4 years being here.