I've used them when they first hit the markert,eh, got popular for mj.
They do work as intended.
They do do something funny to the flavor and nose.In my experiences.
After tinkering and experimenting with them. I found out if your buds aren't close to the target RH of the pack,that's when they either rob terps or impart something to the taste and smell of the buds.Could it be the gas exchange happening while the bovedas are working their magic causing this? IDK.
I've seen the issues and praises of them.
Most issues stem from people trying to dry with them.Putting buds that aren't DRIED in a jar with the pack,thinking they are at the cure stage.
Or,trying to rehydrate overdried bud and blaming that nasty harsh taste on the bovedas.In my situation when I was using them,I found 63-65% bud rh to be my sweet spot for the 62's when I jar.
They are better used for long term storage...AFTER your bud is dried.They will be in the cure zone still,even after they are dried.
Go past 55% and no boveda will bring you back into the cure zone.They will stop the bud from drying out further,if you aren't opening the jar constantly.Again,IMO they are better for long term storage,to keep the buds at in that specific range.
The lifespan on them are pretty damn long.I have some that are still ready to go,and they were purchased over 2 years ago. I did have them in ziplock bags inside of a mason jar tho.No temp control room.Ambient temps.I've had maybe 2 get hard or become ineffective.
I no longer use them.I have a bunch still useful that smell like all the dank nugs they've been in contact with. Ok, well I still use one or 2 here and there when I'm down to the last jar of a strain I know I won't have for a few runs and want to keep that bud nice n fresh.
I use mason jars and hygrometers with much better results.Also my ganja doesn't stay around long enough with rosin,edibles,stoner friends and family for me to justify the trade off of the smell and taste compromise.