I have ISIS RS7s with an UNO spider/c-ring and have been very impressed with them.
iirc when I was researching them matched with a decent BB they come out as light as XTR but for little more than XT money (dep on the BB you choose)
then there's that lifetime guarantee … against *anything* including racing, jumping and DH.
These are much more than niche (although they are that aswell) they're are a very high quality, good value and fantastically performing product.
That they're British just goes to show that you can do these things in the UK without "needing" to charge a premium. Should embarrass some other UK manufacturers IMO