I found it hard to switch layouts, I'm using only one with layers. On first layer there are english letters, second layer there are accents (a → á) and some symbols where accent is missing (m → +). On third layer there are arrows on home row and functional keys. Shift without other key is `(`, on second layer `{`. There are some additional keys at the bottom and middle, they cover the rest of symbols. Outliers are mapped to start editor, browser, ctrl+c, ctrl+z, volume, mute, …
I really like having a single layout. I don't like that I'm no longer able to type on QWERTY without looking at keys. On my desktop, I'm 10 % faster, on any other computer I'm 90 % slower. Would I do it again? Probably yes.