I haven’t been a user of the oh-my-zsh because I found it too complicated. I was only interested in it’s completion features. Therefore I ripped out this component, copied the completions from it and did the configuration on my own.
Then I tried fish-shell but wasn’t satisfied. It lacks completion but has very good autosuggestions and amazing VGA terminal colors for certain types of commands.
prezto jumps in here - it’s an optimized version of oh-my-zsh. It is fast, has completions out of the box, and the nice autosuggestions feature of the fish-shell.