I like the "tabs for indentation, spaces for alignment" style, but it is not always easy for formatting tools as there is no simple way to convert spaces to tab

I like the "tabs for indentation, spaces for alignment" style, but it is not always easy for formatting tools as there is no simple way to convert spaces to tabs, the tool has to be aware of the syntax somehow, or you need to do some manual tweaks. Screwups like missing or adding a space can happen easily even with auto-indent, a common cause is splitting or merging a line, i.e. changing a space with a newline and vice versa. That space character has a tendency to end up where you don't want it, or conversely, get eaten up. When using tabs, invisible space characters can end up between tabs. In the end, on collaborative projects, I usually settle on 4 space indentation, as it is the most common and from my experience, the least likely for people to screw up.