Just saw a video of a colleague burning the silver flex duct we usually see on dryers instead of vinyl. Are these really much better? Are you all recommending solid metal or at least all aluminum ducting?
Why 2 post?
You would not use vinyl or mylar unless wanting to burn the building down.
I always recommend rigid smooth walled dryer vents
Metal dryer ducting is superior, do not forget to clean the duct at least annually to prolong the life of the dryer and prevent possible fires.