Searching for information on why PostGIS may be be a better option for storing raster data, I came across a presentation "Advanced spatial analysis with PostGIS" by Pierre Racine from the FOSS4G conference earlier this year. The presentation as a whole is chock full of intriguing ideas and the summary below sealed the deal for me on using PostGIS for large raster data sets.
In summary:
Why store raster in the database?
One simple language for everything: SQL
Many raster functions are similar to vector ones...Complex spatial analyses can be done with a single SQL query.
Raster/Vector interaction -Your vector data are normally already in the database...
Performance Analysis processing is generally faster on tiled raster coverage.
Data volume - You can work on TB raster coverages without much problems.
You can even keep the raster’s data outside the database...
...and use them transparently inside the db with SQL
Only metadata are stored inside (extent, SRID, pixel type,
nodata) Pixel values area read from the referenced files
via GDAL.