There are a lot of different bike tour options to cycle the Canal Du Midi. In order to make some sort of comparison, it is possible to categorize them into 4 distinct categories.
Tier 1: A tier 1 company is a company that owns their own fleet of bikes, and organizes the hotels and luggage transfers themselves. At a tier 1 company, the entire operation is done in-house.
Tier 2: A tier 2 company is a company that does not own their own fleet of bikes. A tier 2 company is technically a travel agency, and thus they only take care of hotel reservations. Bikes are going to be provided by a third party and will often generate an extra bike hire charge. Luggage transfers from hotel to hotel will be done by a third party as well, such as a taxi. A tier 2 company thus has the most layers of sub-contractors, which will be problematic if a problem arises during the trip (finger pointing from travel agent to sub-contractor, etc etc). A tier 2 company is never present in the region; your only contact with them will be by phone or email. Their local contact is the bicycle rental agency which whom you must negotiate with (in French) about any bike repairs that might be needed during your journey.
Tier 3: A tier 3 company only does bicycle hires. They are often seasonal and often ran from a tent somewhere along the Canal Du Midi. They do not book hotels, transfer luggage, nor provide technical or any other assistance during your bike trip. You are fully responsible for any problems arising during your trip, including bike repairs.
France-Bike is a company based out of Germany and runs complete package tours in the south of France, including one along the Canal Du Midi.
Relax Bike Tours is a company based out of Beziers, France that does bike tours along the Canal Du Midi.
Rückenwind is a company based out of Germany. They run tours in several European countries, including France.
Based out of France, this company runs bike tours in Morocco and France.
Eurobike from Germany is the same company as Ruckenwind.