I use these as my main pick for playing bass guitar. They produce a very nice even bass tone and work like a natural (and musical) compression. I play with a pretty heavy attack and these picks even out my tone nicely but i can still have some dynamic control over my playing. The grip material works really well to prevent slipping.
I have only two problems with these picks. The durability is not the greatest. The grip material wears off and then it gets a lot more difficult to keep playing with the same pick. Also the natural wear of the pick will leave your instrument covered in pink dust.
For guitar I found these picks work really well for strumming parts.
Overall a great pick and I will be definitely getting more of these.
Like many of guitarists, I've tried a good bunch of picks, and I've found that these are the ones I like the most- its feel, its sound, its resistance. I use them for folk strumming and go really really well.