The Uni is a fantastic, stand-alone tool for SRT both ascending and working the tree. Whether it is worth the price will be dependent on how willing you are to incorporate this style of work. In order to make SRT work efficiently for treework positioning, there are many little changes that you will need to incorporate compared to doubled rope.
As has been stated, I don't believe the Uni is fully evolved in its design. It has come a long way and is pretty fantastic to use, but wear is still an issue that can be improved upon.
My initial Uni lasted two years with one rebuild. And I am probably one of the worst offenders for high wear usage. I don't consider the cost/wear component to be of any consequence, because the money it makes offsets that nicely. It is just so obvious that with a change of material the Uni would last tremendously longer.
There are tricks that will extend the life of the Uni. If you climb with it on a tether, it is very easy to incorporate additional friction underneath. I did over 30 70 ft TIP pines recently using a new Uni. I ran a figure 8 underneath for the descent. The fig 8 was new and had grooves worn in it at the end of the job. The Uni had not even worn the anodizing off the cams.
So with a little thought, I am optimistic on a long life for this Uni even in its current state of design.
Dave