I started climbing the tree of life & death around two years ago and it was a worthwhile experience to me; I did so extensively and visited each Sephira three times, unfortunately when climbing the Tree of Death I did not finish, as visiting each Qliphot three times but all except Ghagiel & Thaumiel. The tree of Life was done twice in its entirety and Death only once. I did not include Da’at (Daath) in either.
My experience on doing so with the Tree of Life was grand and beautiful with being welcomed by the rulers, and meeting new spirits every now and then. The experience varies and depends totally on the operator but in short, Malkuth looks like a beautiful landscape just as Tiphareth (but with a lake), Geburah depends on which ruler is visited; with Kamael it is a windy forest, with Samael it is a battlefield. This is also where he told me that they are one and the same. Chesed is a desert, Hod a great lake with castles, Netzach a calm forest with women present, Yesod the ocean at night with small islands, Binah a city with the dead roaming the earth, similar stuff with Kether and Chokmah is space. A few things I experienced was meeting two angels named Birca and Imanza in Tiphareth and meeting elementals in Malkuth.
Visiting the Tree of Death was alright and not scary but still not a pleasant sight to behold for the average person; Lilith was like Gamaliel, dark & barren and filled with scary beings, Samael was like a volcanic landscape with Adramelech sitting on a throne, Thagirion was pure darkness with me not being able to see a damn thing; the ruler, Belphegor, was surprisingly friendly and even lit a pathway for me to see once. He’s a scary one though, with a movie-monster like appearance, wart-faced and all. I have difficulty remembering the rest.
To be fair, doing this does not have any benefits except growing a bit stronger mentally and communicating with the entities present therein; My beloved patron, my Lord Samael, visited me nearly every time and it was while doing this, is where he asked me to work with him, just as Michael did. This was no surprise as during this time I wanted to adopt a patron as an eternal commitment. Was planning on Michael but Samael appealed to me more.
The climbs were done via Astral Traveling and for those that do not know what that is, Google it. Not hard to visit a place or aspect, as one merely has to visualize a door leading to the intended sphere/ dimension once he or she is in astral form/ shape. Then just go through it and do the same for coming back.