As a photographer I have used Thumbsplus for years and can manage and find my digital photos and film scans too. Though it does use a locale database to store the tagging information.
I currently work with my images in concert with a NAS (network attached storage) machine. I have tons of storage space and room to expand and use "virtual drives" to help me organise image data. I have photos from film cameras, digital cameras, microscope, telescope, scanner sources. So I have a virtual drive called "Source images" and I put ALL my source files in here organised by device and since digital cameras automatically name files sequentially I can subfolder sort the source images to groups of 1,000 for easier browsing. Files I work on get COPIED into another virtual drive where I usually est up folder named "YYMMDD - subject name/description" .
I find this works well for me so when I remember I took a blurred photo of an emu about three years ago on a trip to a national park its easy for me to something in my working area taken at or around that time, then checking the metadata (exif) of the files I copied over gives me the source camera and exact datestamp plus the file name so I can always go back to the precise source files quickly if I need to browse for something.
Never used Lightroom, got it with a leica camera and never installed it, maybe I should but with years of organising work invested in Thumbsplus that I dont think can be transferred to another program I'm fine with Thumbsplus for detailed tagging (Which I tend to reserve for final processed images). So I havent needed to look closely at LR, I did try ACDSee once a few years back and it was useless for how I wanted to work and quickly dumped it.
One drawback of image management programs is as soon as you buy a new camera you can't know if the program will ever be updated to support the new RAW image format (I think this is what killed ACDSee for me) So I prefer a file system based process of file management so I can always manage all my files now and into the future. When dependant on a third party package you can't know they will always support all file formats you need or even still be around in 6 months time.
So I return to my first post. EXIF data. It should be a part of all file formats and if you use an exif editor to embed keywords/tags they will always exist in those files no matter the machine you copy them to.
Take a look at
https://en.wikipedia.org/wiki/Image_organizer to get more specific info and programs to look at for your need.
One thing wrong with tagging images is people arent very consistent in their descriptive taxonomy so the in 10yr time you can easily find all Red Ferraris you have photos of, you might have only tagged them as "car" or "automobile" etc. It takes a fair bit of thought to have a consistent way to classify everything in a way that is usable.
Maybe its just easier to get Lightroom?
