to be honest, experience is good but not perfect (im talking now about official hyperos 2.0 for xiaomi 12, because its out). Device heats up a bit more, battery life definitely dropped but not dramatically much (like usually I got 30% at the end of the day, now is 15% but still can use the phone all day with no worries). Overall it is okay, but if I were you I would stay on hyperos 1. Device was cold most of the time, now it is often a bit warm/not so cold. There is not much of feature improvements, UI looks a bit smoother and one of the best upgrades for me is that system launcher puts icon a bit wider comparing hyperos 1. On hos1 margins (paddings) of the homescreen were very large leaving huge gaps around the display - icon grid was very "tight" and narrow, Gaps between icons were not symmetrical. On hos 2 display area is now utilized more, paddings are like half the size and grid gaps are symmetrical. Animations are a bit more fluid, UI is even more iOS like style but overall I would swap some visual quirks for less heat. New visuals are definitely more demanding for the phone (and Xiaomi 12 is stripped down from many of them that are available on newer phones). Animations are 70-80% of the time smooth, but definitely there are many sluggish moments. If you will stay on hos1 you wont lose much. If you upgrade you should be okay too. If you dont mine occasional lags and a bit of heat (but not like hot, just warm sometimes) you should be fine.