Hello, it's early to compare. Miui 10 was a year old and a lot of development put into it. Miui 11 it still in a early stage but in my opinion, it is great. Can't score as high as Miui 10 on AnTuTu for example but that it's not important. I use my mi9 a lot for YouTube, music and gaming. Battery could be better since I notice some battery drain. For example during the night my phone eats 11% of battery when it usually ate 2% per night. Miui 11 just needs some to time to polish. In overall, Miui 11 is great but not as good as Miui 10 for now.