is there a good way of merging 3-4 different iPhoto & Photos libraries while not loosing the data about where the image was taken and format (JPEG, RAW, etc.)?
Open "photos" switch to library containing your "iphoto" file. Photos will convert to "Photos " format and will preserve yopur meta data. It did for me but I did not keep location info as I never recorded it.
As a safety, copy your iphoto file to another location on your hard drive and re-name the extn so that Photos will noit recognize it. You can always rename it if needed later
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