I think both built-in completing read and helm/ivy have their uses. ido is best for when you know what you want and want to get it to it with minimal number of keystrokes. helm seems better for when you want to review many (but not too many) options before deciding on what you want.

I find ido unusable for find-file, because of how it splits up directory from filename. So I use the builtin completion.

But I rarely open files using find-file anymore. ido-use-virtual-buffers is magical. For commonly opened files it let you use switch-to-buffer whether the file is opened or not.

  (require 'recentf)
  (recentf-mode t)
  (setq recentf-max-saved-items 200)

  (setq ido-use-virtual-buffers t)        ; include recentf files

While, something like this works better with helm:

  (require 'yari)
  (define-key ruby-mode-map [(meta h)] 'yari-helm)