org-rifle may be better for searching org notes, because it searches for multiple words occuring in individual notes which is more efficient than simple line-base grepping:
How do you use that day to day? I also use Org, but it has slowed down quite a bit for me. Perhaps one of my files is too big, and I also use the agenda, which takes at least a few seconds to regenerate.
Sure the org mode collapse thing is fine but the killer feature is being able to grep all of my notes in milliseconds.