The Good, the Bad, and the Bagless
Bagless vacuums have been the most popular trend in the vacuum cleaner industry for a number of years now. The Dyson vacuum cleaner company has literally changed the vacuum market (from a marketing standpoint at least) with their line of bagless vacuum cleaners. Hoover, Bissell, Eureka and especially Dirt Devil have really jumped on to the bag-less bandwagon. They all have several if not dozens of bagless vacs to choose from.
Before you go any further, you should answer this question: Do I (or the person who will be operating the vacuum) have allergies or asthma? If the answer is yes, stop reading and research a high quality bagged vacuum with multi level filtration like Sebo or Miele offer.
Most bagless models are not sealed very well enough for somebody who suffers from asthma or allergies (a lot vacuums that use bags aren't either in fairness) and even if they are, emptying out the dirt cup is going to expose the vacuum operator to a plethoeria of dust and debris that was removed from the carpet. Have you have ever had a broken vacuum bag in your vacuum before? That's what your dirt cup if going to look like and the inside of the vacuum around the dirt cup area may also need to be occasionally cleaned, not to mention any filters.
Vacuum maintenance varies from model to model. I'm not bashing bagless vacuums, as some are very good, but for those of you that are have asthma and allergies, move on.
Bagless vacuum can be easier to take care of. The important thing for a vacuum owner is to change your filters with some kind of regularity. Clogged filters can damage a vacuum. At the very least you will be increasing emissions produced by the vac when it is being used. Bagless vacuums are a bit more convenient because most filters last 6 months to a year. Vacuum bags are a pain in the butt to find, so I can understand why you would want to avoid any dependencies on them. Vacuum filters end up being equally difficult to locate over time. Some vacuum brands like Hoover might continue to reuse a vacuum cleaner design over time and they just make suttle changes to make the vacuum seem current. That can be a good thing for people who bought one of those vacuums because parts and vacuum filters will remain available and easy to find for a longer period of time.
Overall, most vacuums that utilize high qualtiy vacuum cleaner, an exhaust hepa filter, and some kind of pre-filter should provide a healthier environment than a bagless vacuum. That's not always the case, but more often then not this is the reality of things. If you want a bagless vacuum cleaner, buy a couple of back up filters when you purchase the vacuum. That will maximize the convenience of bagless vacuum ownership.
During our research we found Dyson made the most popular bagless vacuum cleaners available, but they are that not cheap. If you don't want to spend that much money, we would recommend you shop around for a Eureka, Hoover, or Bissell in that order. These 3 brands offer bagless vacuums for under $250 that will probably be sufficient for cleaning your home.