The vast majority of armodafinil sold online is derived from Signature (sister company of Hab Pharma)  or Sun pharma (Sun Pharmaceuticals Industries).
These are reputable pharmaceutical companies based out of India. India does not have the same intellectual property protections as the United States, which allowed them to manufacture armodafinil even when the drug patents were active. At the moment both the armodafinil and modafinil patents have expired.
When buying armodafinil online, you basically have four choices:
Waklert (armodafinil manufactured by Sun Pharma)
Artvigil (armodafinil manufactured by HAB pharma)
There are two manufactures (HAB and Sun pharma), and two different versions of the armodafinil drug (Waklert and Artvigil). If we compare Artvigil vs Waklert  we will see they are chemically similar and there are numbers of reviews where people prefer Artvigil over Waklert and vise versa.
Waklert vs Artvigil -  which is the better brand?
What's the difference between Sun Pharma Waklert  and HAB pharma Artvigil?
Lets look closer to Waklert vs Artvigil manufactures. Both companies are based in India
Sun Pharma has been manufacturing Waklert for decades; HAB and Artvigil is relatively new Both manufacture pharmaceutical grade armodafinil
Since Sun has a longer track record, they charge a premium compared to HAB (HAB is cheaper)
Some people swear that Sun pharma Waklert is superior if to compare to Hab Artvigil but as far Sun just has the first mover advantage
Many people compare Artvigil with Waklert and it has been proven by many users of Waklert that Waklert is a far better option when it comes to dealing with sleep apnea and other sleep related disorders. For one, a 150 mg of Waklert pills gives a liitle  stronger effect on the body than a 150 mg of Artvigil  pills. Waklert gives a stimulation which is a bit  stronger and also helps to control and reduce your appetite. In comparison, Artvigil  is definitely a more pleasant soft stimulation drug, whereas Waklert will keep you going even under harsh conditions.
This again also depends on what you are using it for, but if you are targeting at increased alertness and wakefulness after a shortage of sleep, Waklert is recommended as a better brand by 65-70% of reviewers.However this can be due to a fact Waklert is old and well advertised brand on the market while Artvigil is still relatively new. There are many online reviews where people prefer artvigil over waklert due to lack of headache.