The disposable bags are, for me, very expensive after adding shipping and customs. The cost of US$8.50 - $9.00 each comes to mind. I do, however, consider them a necessary expense as the Festool dust collection makes a tremendous difference to what I do and where I can do it. I considered buying the long life bag but I bought a cyclone instead. When planing I was getting through several bags in a day and resorting to cutting the bags open and taping them up again. The cyclone has almost paid for itself in bags saved and I am not a daily user (I have a day job to pay for the tools!). I also no longer have qualms about what I suck in. As I am doing mostly general building type work cement dust, sand, sawdust, shavings, sanding dust and grit all go whistling (and occasionally clanking) into the metal bin I collect in. I take the bag out of the CT-22 and visually check the inside occasionally as there is often a build-up of fine particles. Mostly I think it is stuff in suspension or in the hoses when the unit starts up that gets through the cyclone to the bag. So I do find that I need to replace the bag once in a while.
There are several advantages of the container versus the bag. One is the oopsy factor such as when one accidentally sucks up that missing nut. It's far easier (and less messy) to retrieve it from the can than a bag. Another is the ability to put a trash bag over the open top of the container and tip it up. Done with reasonable care there is no airborne dust or shaking of bags. I can also hose out the container if needed.
The only drawback is the need to create ones own base that mounts the cyclone on the container and onto the CT. I still have not had the time to get that right.
I think that there is a great opportunity for a Festool designed systainer sized base cyclone add-on. My solution opened up the opportunities for using the dust extraction system for me as I am sure it would for others. There is a whole thread on the cyclones and has some great insight and information into the various options.
SteveD