I posted a write up on these when they first came out. I'll go and find it later on and post a link. But for now:
1. Very expensive for what they are;
2. Something of an improvement on the original blade clamps (by original, I mean what was fitted originally to my Exc 21, bought new in 2015) but IMO, not enough of an improvement to justify the price.
3. Very "pretty" looking, (if that's your bag).
As said I'll come back with a link later on and you can judge for yourself - stressing JUST my own opinion, and I'm NOT an expert.
Edit to add link:
Sorry it took me so long Chris DT, but here's the link/s:
https://www.ukworkshop.co.uk/threads/excalibur-scroll-saws-background-updates-to-my-machine.115659/
As that post was made before the "new" UKW Forum software, you'll find the link contains several other links to .pdf files. Sorry about that, but just FYI, when you see a .pdf file listed you just double click on it and it will open on the same screen. If you just want to read it, just carry on. But if you want to save it to your own PC you just right click and use the "Save As .... " command. (Sorry if that's teaching granny to suck eggs)!
Anyway, HTH