Almost all the Shroud covenants have negative effects to make them unwanted. Most people recommend you not play Psionic more than once, unless you really just love gambling, but if you do decide to go through it anyway, the Composer of Strands is the least likely to hurt you. It still can, though - it'll randomly change your genes and you can't change them back. You could also do End of the Cycle if you know you're close to the end of the game, but it's basically game over fifty years after you accept it.
Other affects from the Shroud include temporary buffs, temporary debuffs, and leader deaths. If you have a Chosen One (a slightly better than average leader created by a Shroud interaction), don't have him talk to a presence in the Shroud because there's a chance it'll kill him, and you won't get another Chosen One. If you're very lucky, you might also unlock psionic ship equipment at a time when it's useful, but that's up to pure luck. Psionic is better than a kick in the head thanks to the pop buffs, but eventually you'll stop contacting the Shroud because it has virtually nothing useful to offer you.
The highest recommended ascension right now is the Synth ascension. It offers the greatest amount of pop growth and a flat 20% production bonus to all pops. Bio comes in second place, but at a class below because it really doesn't do as much - it's the only option hiveminds have, though. Psionic rarely ranks for consideration. Basically, if you take it, expect to be punished about 40% of the time and then get surpassed by every other ascension anyway.