Malcom at cc has said that the only negative is the weight. Positives are more control, a feeling of bottomless travel, improved pedalling ability without a comprising on the ability to handle small bumps. Improved action on multiple hits, less stiction. Basically if you dont mind the money which is a lot or the weight which again a lot, about a pound more than a rp23 then there are no negatives.
Steve Jones also rates the shock as being on another level.
Oh and I dont thing Ti spring is an option as its not available in that size,plus it is supposedly better to run more sag than normal on the shock as its more controlled. So i would not like to buy a Ti spring straight away only to find out it was the wrong weight!
I missed the MBR test last month due to being in France, if anybody would like to share what they said or could send me a scan of it would be much appreciated.