Pros Could be a good paperweight or used by a security researcher who wants to keep abreast about the latest viruses and spyware.
Cons Xiaomi App store is full of viruses and spyware
No Google Play access
Slow, sluggish phone
Terrible, unstable OS
Phone Reboots constantly
Summary The Xiaomi app store is the largest source of malicious code I know of. All, and I do mean all of the non-Chinese apps are pirated and full of viruses and spyware. Xiaomi blocks Google play. The operating system is extremely unstable and buggy. The phone itself is very sluggish due to the slow processor and low RAM.
Stay away from Xiaomi. You are better off with two cans and some string.