I've been taking this once in awhile recently, here are my thoughts:
Phenibut is a lot more powerful than I was expecting - I was expecting it to be more of a "supplement" with slight mood lifting/anti-anxiety capabilities.
However, I found when taking more than 2g of it, I kind of "trip", in a weird way. I start by feeling drunk, with a similar buzz, but after awhile...difficult to explain this, but it's like dreams start leaking into my conscious state, for example;
I'll be sitting down at the computer, and i'd have a very small conversation with someone, and suddenly realizing I was sitting staring at my screen blanked out for half a minute, despite that "conversation" seeming so real.
I also get constant sleep paralysis (bad) and lucid dreaming (good) (which I thought were some recent ADs I was on, but off them now and it still happens when I take phenibut)
All in all, my experiences with phenibut are that it's a "blank out and dream for a moment while feeling mildly drunk" sort of drug. Yet it makes every sleep an adventure in itself...I really like the feeling waking up in the morning and being able to recall several dreams in detail.