I play mandolin and prefer heavy stiff picks - eg Jazztone 208s, Big Stubby 3mm. So obviously I had to try these. Alas they would require a new and completely different right and left hand technique to be playable on mandolin for anything other than strumming 4 note chords - and even that requires a very different approach to the normal.
There are two problems -1. basically mandolin strings are too close together in their pairs and between their courses for these very, very thick picks to strike cleanly. The only way to get a decent sound is to strike the strings very much harder than with a normal pick and it's also necessary to pull off / mute slightly with the fretting hand. Which brings us to problem - 2. the sound is very, very dark, thumpy, like palm-muting - it doesn't ring at all. I guess this could be fine for chording in some styles of music (maybe for a bluegrass chop) but it's not really something many ( if any ) players are likely to want for melody playing. It certainly won't help if you want to sound like a Gypsy Jazz player.
Having got all that off my chest I can see why an acoustic or electric jazz player or indeed a bass would like these. They are very solid in the hand - won't slip at all and at the same time are silky, smooth and fast on the strings.
