Who makes the best robotic vacuum cleaner?

Consider the following: 1) the filtration system, 2) the suction power, 3) maintenance 4) extras 5) warranty and 5) the carpet agitation.

Filtration system - A vacuum with a HEPA filter is good as it makes the air in your home generally cleaner.

With or without a Bag - Bags are disposable but some can be cleaned and re-used. Bags are cheap in the short run but buying bags can be expensive over time. Bagless vacuums are more convenient.

Suction power - Don't just look for a vacuum that has too much power but no support from quality locks and parts. Some vacuum cleaners have adjustable suction good for mixed floor types.

Maintenance - The best vacuum cleaners are bagless which simply means you don't need to keep buying bags to use the vacuum cleaner. It's worth noting that vacuum cleaners with bags are usually cheaper because you need to keep buying bags. In the end, the cleaners end up being more expensive and offering you less value for your money. Bagless vacuum cleaners are easier to maintain especially those that have dirt cups that empty from the bottom automatically.

Extras - You should also consider the extras that come with a vacuum cleaner before you decide if the vacuum cleaner is worth buying or not. The best vacuum cleaners come with plenty of extras i.e. extra nozzles, brushes, crevice tools, etc. that make cleaning seamless and thorough.

Carpet agitation - Effective vacuuming requires the carpet to be agitated to release the dirt and grit. Look for something that has a rotating brush and/or a beater bar.

Warranty - This goes without saying. You should never buy any appliance, let alone a vacuum cleaner, that doesn't come with a warranty. A warranty is a testament to quality. Appliances that come with warranties rarely break down and if they do, the manufacturer covers the repairs. Any vacuum cleaner with a 1-year warranty and above is worth buying. It's also worth noting that a longer warranty is always better.

Some brands you might want to consider - Dyson, Miele, Hoover, Nilfisk, and Windsor. It depends on what you are looking for at features and price. I've always heard that the Kirby was the absolute best machine on the market but I've had a Simplicity Commercial for 18 years now and its showing no signs of quitting on me, I've had it serviced twice and the original cost was around 450.00.

I would have to say the Dyson Ball Vacuum, Panasonic MC-CL945 &Electrolux Ergospace EL4103A vacuum cleaner !

I would definitely have to say the Dyson Ball Vacuum. Link to informative site below.

the Oreck XL