I have settled on Sessions instead of Catalogs as my primary workflow. There are a few reasons I have decided on this over Catalogs. The biggest reason is being burnt by Catalogs and the cryptic folder structure if and when you need to recover files due to a failure. I have had backup disks and Catalogs from the past fail to open and could not recover the RAW files other then digging through the file system looking for files. For some reason there are more folders then files and it takes hours to find the files and readjust them.
Sessions on the other hand has a very simple and logical folder structure that can be easily reloaded by folder. You create the folder name when you do an import or process files instead of the Catalog system so this has your logic and not some programers logic.
The other big advantage I like is I can connect a USB drive and find the Session and work directly from the USB drive instead of loading everything on my computer drive. I pay a little penally on speed but generally I am looking for just a few files to adjust and process so not a problem. Not sure how this would work with a Catalog. I still have a few years of backup disks that I need to rip apart the director to find the RAW files!
Hope this helps someone!