Someone said, “Try reading Aldous Huxleys Perennial Philosophy”

Soh replied, “Thanks for the recommendation, will look into it. But I have to say, I understand but do not agree with perennial philosophy (The perennial philosophy, also referred to as perennialism and perennial wisdom, is a perspective in philosophy and spirituality that views all of the world's religious traditions as sharing a single, metaphysical truth or origin from which all esoteric and exoteric knowledge and doctrine has grown.)

There are similarities but also differences in views and realisations.

As Christian mystic Bernadette Roberts said, 

"That everyone has different experiences and perspectives is not a problem; rather, the problem is that when we interpret an experience outside its own paradigm, context, and stated definitions, that experience becomes lost altogether. It becomes lost because we have redefined the terms according to a totally different paradigm or perspective and thereby made it over into an experience it never was in the first place. When we force an experience into an alien paradigm, that experience becomes subsumed, interpreted away, unrecognizable, confused, or made totally indistinguishable. Thus when we impose alien definitions on the original terms of an experience, that experience becomes lost to the journey, and eventually it becomes lost to the literature as well. To keep this from happening it is necessary to draw clear lines and to make sharp, exacting distinctions. The purpose of doing so is not to criticize other paradigms, but to allow a different paradigm or perspective to stand in its own right, to have its own space in order to contribute what it can to our knowledge of man and his journey to the divine.

Distinguishing what is true or false, essential or superficial in our experience is not a matter to be taken lightly. We cannot simply define our terms and then sit back and expect perfect agreement across the board. Our spiritual-psychological journey does not work this way. We are not uniform robots with the same experiences, same definitions, same perspectives, or same anything."

Acharya Mahayogi Shridhar Rana Rinpoche, who went through went through realisation of atman brahman and was confirmed by his Vedantic masters as having realisations that were deep and profound, later felt unsatisfied and by dwelling into Buddhism, attained the Buddhist realisations and continued to spend decades in retreat and was asked to teach by his Buddhist teachers. 

As I wrote in http://www.awakeningtoreality.com/2013/01/marshland-flowers_17.html , “As one of the few great Buddhist teachers in Nepal where the majority of the population belong to the Hindu faith, a place where myths and misconceptions of Buddhism are abound, he is in a great position to correct all of these misconceptions and do an accurate and unbiased comparison between the teachings of Buddhism vis-a-vis Hinduism due to his deep knowledge and experience of the Buddhist teachings as well as his previous experience with the Hindu tradition. He emphasizes that the comparison was done not in order to demean one system of teaching over another but to provide greater clarity on the essential doctrines of each system so that they could each be understood correctly, as he says, "I must reiterate that this difference in both the system is very important to fully understand both the systems properly and is not meant to demean either system."”

Also my mentor Thusness wrote years ago,

““Yes sahaja samadhi but that remain as "experience".  Just like in taoism, it is all about naturalness 自然 and non-action (action without agent) though there r overlaps but they r different in praxis and view essentially.  There is no need to forcefully integrate the various religions into one, that is just more attachment.

Although there is no monopoly over truth as ultimately all is/are talking about one's primordial nature but there r those that much clearer and precise in their system of practice.  If the views and philosophies r 90% inherent and dualistic, the result from such a system will at best be a stage to be achieved abiet the emphasis of" natural state".

As I said b4, if someone were to say "Soh is a malay, a speckie, used to b a c# programmer, 1.9m tall and has a sister", obviously some informations r correct and some r misleading.  Even if u were to stand right in front of him, he will not b able to recognize u.  Therefore although all r talking about the natural condition of pristine consciousness, some r exceptionally clearer than others.”””