This is interesting, thank you. Although, there is something to add to this discussion.
I still open Leap on occasion as it is a similar application to HoudahSpot. I still prefer HoudahSpot and I am not suggesting that anyone leave HoudahSpot for Leap. However, there are still one or two things I can do in Leap that seem to be missed by HoudahSpot.
I notice that when I have an unmounted external drive with a running saved search (template), HoudahSpot and Leap behave in different ways. Neither one will produce results, or show errors, but the search results will remain empty.
In this example the search is set to an external volume that is not mounted. When I mount the external volume that contains the targeted files in the search, and the search is still running, Leap will suddenly populate the search as it has now found the mounted volume. When I do the same thing using HoudahSpot, nothing will happen. The search, though still running, will not suddenly populate the search results when the drive is mounted. With HoudahSpot I have to stop and restart the search before it can find the files that are on the newly mounted volume.
This means that, regardless of how an unmounted file is indexed and whether it may be available as per this discussion, which is a good idea that I will look at BTW, Leap can still pick up a missing external volume from a running search as soon as the external volume is mounted, HoudahSpot can’t. If the volume was missing when HoudahSpot started the search, the volume will remain missing until the volume is again mounted AND, HoudahSpot gets the search re-triggered.
On a side note concerning the other main observation I have as to what Leap does differently and better than HoudahSpot currently is set up to do, Leap can search within the found set displayed without having to reset your search parameters. HoudahSpot will do this only for certain search criterion, but not for others. For example, when I want to search through my search results to locate a file with a specific Finder comment, searching in the found set will instantly locate those matches. With HoudahSpot, I need to change the search criterion in the base level search, start the search over again, and include “find in Spotlight comments” before I can do this.