My Xiaomi becomes impractically slow around 15% (probably less, I've not properly measured). My Boosted Rev, I've yet to find anything in the Redmond, WA area t

My Xiaomi becomes impractically slow around 15% (probably less, I've not properly measured). My Boosted Rev, I've yet to find anything in the Redmond, WA area that it won't climb with gusto. The Boosted cost $1600US, though.