It is true that the Gaudiya Vaishnava`s and some other religions prefer a dualistic approach,and dislike the Advaita Vedanta philoshophy which begins with Oneness,but even the devotional paths end up with the One at the point of Self-Realisation,which is experienced by all spiritual seekers at the point where their consciousness reaches boiling point and the false ego dissapears,and the Self,which is the true Self,is then revealed.This is experienced by all enlightened people no matter which philosophy or path they choose to follow,and is actually the same experience of Chaitanya and Shankara,only their individual means of expression differ,so it is that whenever a new person becomes enlightened,the expression is always unique,as unique as that persons soul,and bodymind.But the One is always experienced when the ego-mind is trancended,for devotees of Krishna they may see Krishna in everyone and everything,as did says Chaitanya,"when you see Krishna in everyone`s eyes you are free".This experience will happen to the mature devotees of Krishna and other forms of God and has happened to many devotees,Ramakrishna,and devotees of Shiva alike.It is the same self-realisation that happens to those who are not devotional in nature but find liberation through Jnana or purely meditation practices.I dont mean to say that Self-realisation is the ultimate realisation,there are also the Paramatman realisation which transcends the Self,and the ultimate Nirvana Kaya or seventh body,but the evaporationof ego,and Self realisation has to be the common experience of all mature spiritual seekers,when they are ripe for it.