It is obvious from the foregoing discussion that Sikhism belongs to the mainstream of Hinduism in its theology and cosmology, in its fundamental visi… - Ram Swarup

It is not that there are different Purushas to experience but the same Purusha is experienced differently at different levels. There is the experience of Divinity at the level of purified manas, but the same is also experienced at the level of buddhi. ... In the first, the experience is more particularised; in the second it puts on a more universal aspect. ... Manas particularizes; buddhi generalises. In the movement from manas to buddhi, spirituality rises from a spiritual experience to a spiritual truth. .... One need not grade the two experiences but one should try to understand the difference between them. At the level of purified mans, there is faith, joy, sonship, prophethood, inspired utterances, luminous visions, chosen destinies, unique roles.... (p. 101 ff)

He only quotes from Rabia, Bayazid, Abu Sa'id and Rumi who do not properly represent even the sufi silsilas, the mainstream Islamic Sufism.

The Vedic approach is perhaps the best. It gives unity without sacrificing diversity. In fact, it gives a deeper unity and a deeper diversity beyond the power of ordinary monotheism and polytheism. It is one with the yogic and the mystic approach... In this deeper approach, the distinction is not between a true One God and false Many Gods; it is between a true way of worship and a false way of worship. Wherever there is sincerity, truth and self-giving in worship, that worship goes to the true altar by whatever name we may designate it and in whatever way we may conceive it. But if it is not desireless, if it has ego, falsehood, conceit and deceit in it, then it is unavailing though it may be offered to the most true God, theologically speaking.