Quite often a suggestion will start with what I want, but later lines I don't want to accept.

With Supermaven code completion, you can set a bind called 'accept_word', which allows you to gradually accept the completion.

Here's an example of what I mean:

It's a much faster workflow that accepting the whole completion, then deleting the bad bits and starting over.

This is the killer feature that's stopping me from making the switch at the moment.