I have a Carbon Ultima on one bow and a Dual Click Carbon Extreme (carbon extension and vertical track) on the other.
I prefer the adjustment on the dual click - probably because I've been shooting that type of sight since 96. Old dog new tricks - you'd think it was a "small" difference but i still need to look at the vertical adjustment on the Ultima to make sure i'm going the right way
I don't like the plastic block on the DC and I have seen these with cracks and stress marks. Although mine is still OK.
However there is no question that on my bows (RX and HPX) the Ultima is quieter in use. I have seen a few Ultimas "wear out" but not sure why - some seem to just keep OK with masses of use, others seem to deteriorate. I do wonder if there was a "not quite right" batch maybe 2 or 3 years into the production.
I like the feel of the
Shibuya Carbon extension - didn't like the alloy extension Shibuyas or the
Sure-Loc extreme but that is personal. Like the difference between feel of forged and billet machined risers. You tend to just prefer a feel.
Mind you when I got my Ultima it was ?145 which was a bit more palatable! However I'm sure here will be a bunch of Axcel's and Ultimas on eBay in the near future as the "must have the latest gear" folks upgrade to the new Axcel sight
I would say that if you have problems with bits of kit shaking loose then chances are there is something not right in your setup - tiller, brace height, arrow weight etc. Look there first before changing kit. Mind you I have seen stuff that seems to not work due to incompatibility in a specific setup - usually the issue is just noise though.