Ivy vs Helm
You have two major packages in Emacs for incremental completion, like when you are typing a M-x command or looking for a file. They are Helm and Ivy/Counsel.
I started out using Helm, but the last 2-3 months I have been a Ivy user.
Helm is older, than Ivy. And it is this large monolith. There are some good and bad sides to that. The bad side is that it takes longer to load than Ivy, but you do not need to do much with it once you install and enable it. It work more or less like you expect it to. I don’t think I had a lot config with my Helm setup.
Ivy on the other hand is a lot lighter. It was the first thing I noticed when I started to use it. Emacs loaded faster, all the Ivy interfaces were noticable snappier. But you will spend some time configuring to be like you want it to be.
Your needs may be different. But I would give Ivy a shot, if you think helm feels a little bit slow.