Canon 70-300 IS USM vs 70-300 L IS USM

Thanks. Yes I see that the 55-250 appears to be sharper than the non "L" 70-300. When I replaced the non "L" with the "L" the 55-250 fell way below.

I now expect that.

However, if the focus on the 55-250 is either slow or inaccurate, it doesn't matter how sharp it is.

Another thought. Unless the non "L" 70-300 focuses much faster and better than the 55-250 why doesn't the non "L" disappear? Unless maybe it does focus much better.