It has been quite effortless to delete or replace words or lines but every time I've tried getting more adventurous with it - say, surround every line of text with double quotes etc, I end up finding the commands unintuitive or hard to remember.
There's also an issue with my older muscle memory of `CMD+Z` which works on a different stack than `u` and `CTRL+R` and I end up messing up my code.