Every time I've tried helix, as a staunch neovim user, I've run up against frustration at the selection-first approach. In helix you have to select the function first, then delete it. In neovim I know that daf will delete the function and the line below it if there is one.

It's not better or worse IMHO, it's just different enough that it requires me to go from thinking action-modifier-movement to thinking movement-modifier-action. I'll probably keep giving it a shot every year or so though, always useful to try tools and see if something fits you better than what you have.