Personally I have found DeepL to be more accurate in the languages they support than Google Translate. They used to support much less, but for the languages it did, it was pretty great. It supports way more now though!
Yet tiny European languages like Latvian are supported, as are very difficult translation targets such as Estonian and Hungarian.
My hopes are dashed every time they add another tiny European language and Turkish remains off the table. :-(
> do you have some metrics you can share?
Not really. Try to have discussions using DeepL and Google Translate. Ask native speakers which one was more accurate and whatnot.
I do not know French, but DeepL allowed me to speak to someone using the language, and apparently at some point some people thought I was a native speaker!