Helm and Ivy are the two big systems for doing “completion” in Emacs.
Both of them are supported by Spacemacs.
They do more or less the same thing. It helps you to do what you are
trying to do, either by completing a M-x command or figure out method
names or class properties when you code. And a whole lot more.
I have used both, and the differences are minor. Helm is a little bit
more full featured and always does what you expect. While Ivy is faster
and more minimal.
I’m going to stick with Helm, because I’m so used to it, and I think it
is a little bit easier to work in in certain areas. For example the M-x
auto-complete are much better in my opinion. But, if you want something
smaller, something faster or prefer something more minimal I think Ivy
is a good option. And I would be perfectly happy with Ivy, if it was the