Hi,
From my experience, performance (FPS) and drift is worse in 2.1.0 than in 2.0.0, as I pointed out here, with 2.0.0 being slightly worse than 1.3.3 as well.
I just tried 2.2.0 and found FPS to be around 20% lower than 2.0.0, and very noticeable drift 
Has anyone else had a similar experience with this new version?
Based on these findings, and taking into account the rest of the comments on this post, I think I’ll stick to older versions for now. I am aware that I am losing many new features, but as @Manos_Tsotros said, performance and stability are essential, especially considering the huge fragmentation of the Android market. Hopefully Niantic will fix these issues in future releases.