The notorious question of the decade. What's better - bagged or bagless. Being as objective as possible, I will explain my views on both, throw in a few facts, and let you make the decision.
Bagged Vacuum Cleaners:
Bagged, in my opinion, is the better option. Disposable bags are much cleaner to dispose of. In the past, most vacuum bags were made of 2 ply paper. They were much more porous than the bags today and leaked the fine dust and dirt particles back into the air. If the vacuum included a cloth or vinyl bag, the micro fine particles are still released into the air. If the vacuum had a hard plastic or metal housing, the dust would accumulate on the inside of the bag housing.
Disposable bags today have come a long way as far as filtration is concerned. A lot of manufacturers construct their bags with 3 plys or more, or use a cotton type liner that filters the exhaust air even better than the standard paper bags. Some use a spun cotton material that is far superior to the paper, and captures the very small dust particles. Each manufacturer has a different name for their bags. Words like Filteraire, Micro-Lined, Ecopure, Intensive Clean, and Micro Fresh are just a few of the more common brand names. When you are purchasing one of these brands, you are buying a bag that is a little more expensive but is manufactured to a higher standard of filtration. Most also include some sort of closure or cover on the top of the bag. This will ensure that the dust particles stay inside the bag when it is disposed of. Bags of these types usually cost $20- $30 per year, depending on how often you vacuum.
Bagless Vacuum Cleaners:
The Bagless Vacuum Cleaners today are all the rave. They usually have a clear, hard plastic container that captures the dirt and dust. When it's full, you simply remove the cover to dump out the dirt. To avoid having all of the dust and dirt flying into your face, I recommend taking it outside to dump.
To keep the dust inside the container and not being exhausted through the motor, these types of vacuums will usually have 2 or more filters. One is a pre-motor filter and the other is an exhaust filter. Some models will also include a HEPA filter. These filters need to be maintained regularly. Most can be washed several times before replacing. When you wash your filters, make sure to let them dry outside of the vacuum for a least a day before returning them inside the vacuum. If not completely dry, mold and mildew will grow, and you WILL smell it. At this point, replace the filter with a new one. Lifetime filters also need to be replaced. After several washings, they will start to deteriorate, so lifetime, isn't necessarily so.
Bagless vacuums also have rubber gaskets that will need to be maintained. Keeping the gaskets free of dirt and dust will keep the seal leak proof against the dirt container. Replace them if they become flattened.
I hope this information has been helpful in making a decision on what type of vacuum works well for you. Make up your own mind, me I'm going with the bagged models. They're cleaner, and less costly than the bagless models. Happy Vacuuming!