Pros:
So many options for positioning, it is really fantastic in that respect. Also very comfortable, surprisingly so, given that it's ended up sitting almost behind my jawbone rather than under the chin itself! But that allows me to 'cradle' the fiddle more, and have better control, and it doesn't chafe or dig into me. Also it is best for me to have it set quite a lot further to the right than any other chinrest I've ever had, which also seems to suit me. It definitely improved the tone of the fiddle, too, allowing it to ring out more. Very lightweight indeed, an all-round freeing up of both the instrument and me!
Cons:
Ummm - the price?! But I certainly wouldn't want to be without it now!
And I feel a little guilty that I have four spare springs that I'm unlikely ever to use - it'd be good if unwanted springs could somehow be returned so someone else could use them!
Instructions leaflet could've been clearer, as until its settled and you're using it, it seems quite complicated.
Other:
No-one else who's tried my fiddle has liked it - but that's maybe because its placement is so unique to me - they'd probably have had to adjust it for themselves, but there's never been time for that in a session!