One of the major resons why westerners prefer the monism of shankara is the negative experience they have had with dualistic Christianity.Christianity enforced a strict dogma upon the population , banned reason and burned all those who questioned it , the unfaithful , on the stake.The rigidity of the Church and its intolerance has forever biased Europeans against dualism.Plus it enforced a strict morality that did much harm to the people , and was for the most part unscientific.
In the monism of shankara , they find a philosophy that is free from absolute moral notions of right and wrong and instead introduces them to the path of Yoga , whereby one transcends the limited notions of morality and attains to the brahmic consciousness.This idea impresses itself pleasently upon Europeans who are tired of church restrictions taken to absurd lengths.Plus the idea that all this is an expression of Brahman is a good one as it engenders respect and love for all creation.It also goes against the church view of a God separate and cutoff from the universe , a Sky-God who is separated from his creation.Plus modern science , especially darwin's evolution and modern cosmology starting from Johannes Kepler goes against the creationist view of the church.Shankara's monism does not contradict modern science and many like Frithjof Capra and Deepak Chopra have proven that advaita is in consonance with quantum mechanics and special relativity , and could even be the Grand Unified Theory that scientists are seeking.
Plus many people are uncomfortable with the idea of God as a person , sitting somewhere above influenceing events.They are more comfortable with the idea of an Impersonal Brahman , which advaita posits as final and real , the personal aspect being necessary only for the ordinary people.Since God is different from man , and man has an ego and a physical body , ppl think God has to have no ego and no body , thus impersonal conception is the right one.Thus God is an energy field or a consciousness field of which we are a part , but we have not realised it.
Also advaita tradition has become associated with Yoga and Mysticism , thanks mainly to the pioneering efforts of Swami Vivekananda who brought Yoga to the USA , and Raman Maharishi , the saint of Thiruvannamalai , regarded as the greatest advaitin in modern times. RM enjoys quite a reputation as a realised soul and his didactic way of answering questions has made him into a mysterious personality.
All this naturally biases westerners against Madhva and his philosophy.They see in that philosophy a mirror image of Christianity , a God seated in the heavens who creates the universe , delivers his devotees , and punishes the evil , consigning them to eternal damnation.The last item naturally makes one think that Madhva was influenced by christianity.
But if we see carefully , there are a lot of differences between dualistic christianity and dualistic metaphysics of Madhva.
1.Firstly dualistic christianity is a tamasic religion , based on blind faith of its followers to the doctrine of Father, Son and Holy Ghost.One may not question any event in the bible and take everything they as gospel truth.If reason contradicts the bible , it is The Book that prevails , not reason.
But madhva on the other hand places a lot of importance on reason.In fact he says that scripture should not contradict observed worldly phenomenon and places pratyaksha and anumana and worldly experience as valid pramanas, or sources of correct knowledge and points out that Vedas never contradict worldly experience.So great has been his insistence on Logic , he and his followers have been called as Pracchaana Tarkikas , or disguised logicians.
2.Secondly while God of the bible is a sky-god , separate and distant from his creation , and man is the Lord of this world, in M's system , Vishnu is both transcendental and immanent.He exists in far off vaikuntha and also in every one of his creation , animate and inanimate.He is both Anu and Vibhu.Isha vasyam idam sarvam.All this is for the habitaion of the lord.The lord is a part and parcel of the creation , he is involved in it , yet he is detached.He is everywhere.
3.In regard to Yoga and Mystcisim , lets not forget that the tattvavaada tradition boasts of great Yogis , Madhva being the greatest of them all.Another great mystic was Sri Raghavendra , famous for his use of Yogic powers for the benefit of mankind.
And we should remember that Patanjali's Yoga sutra itself is realistic and dualistic , its just the advaitins have interpreted it in a monistic fashion.
4.And Madhva's system does not prohibit meditation on the impersonal aspect of Vishnu , his brahmajyoti.In fact Vishnu is both Perosnal and Impersonal .Generally its difficult for the common man to meditate on the Impersonal absolute , but those can are free to do so.But Madhva does not say one aspect is superior to the other.
5.Schopenheur discribes christianity as the religion of pessimism.He delineates it as its defining character.Anybody would note that suffering and sin are its primary concepts.
On the contrary Madhva's system is an optimistic one.He advises mankind to be optimistic as Krishna is the friend of the human peoples and is ever ready to rescue them from their difficulties.Ones friends may abandon him , his wife may abandon him , but Krishna never abandons his devotees.Na me bhaktya pranasyati.My devotee never perishes.
The idea of bliss , Ananda is the predominating one , not suffering.Madhva points to Krishna as the source of eternal bliss , sense pleasures being of a temporary nature.
6.We must also realise that while Madhva talks a lot of heavens and hells , the main focus is on Vishnu.He claims that Lord Vishnu's grace is greater than all your bad karmas put together.Vishnu is a loving god.We must try to love him and not fear him.This is different from the church's conception of a god whom we are supposed to fear , who wrecks vengeance on the unfaithful.In fact at the end of the Pralaya , Vishnu is willing to forgive the demons for their sins , but it is they who wish to go to hell and suffer rather than seek forgiveness from Vishnu.The nature of the demonic souls is that of suffering , and in one way , they enjoy being in hell rather than serve Vishnu.
One must understand the difference between the two types of dualism , one born of tamasic consciousness and the other born of pure sattva.