I have used for many years iView, and then Expression Media to catalog my files, and I must say that even today I did not find nothing better from this point of view (on Mac).
As the actual one is very limited, it will be very nice to implant some more powerful search/find function in the LR Library module.
Something that allow to make very precise researches like, for example:
"Find all the tif or pdf files with a weight > 1 000 000 bytes, a resolution of 300 dpi, an Adobe RGB profile and 16 bits of depth..."
Image is not available
It will be very nice too to have the possibility to personalize more the info on the preview module (for example somebody could be interested to see the weight in MB of each file, of the embedded color profile, or the resolution, or the depth of the file):