Nothing out of the park, I use mainly apple or sometimes cherry in my cold smoker. You don't want an over-powering smoke, but rather a compliment of smoke.
I also put pieces of apple into the cold smoker to try and add more flavor. Does it work? I don't know, but as long as I think it does, that is all that matters to me.
Humphrey's DownEast Beast W/BBQ Guru