Trust me on this one, I've tried both in the tree extensively--The Sidekick is not perfect, but it beats Sherrill's Reach tool hands down, IMHO.
Why? Because the Sidekick locks at every section, you can climb with it on the saddle without it opening and getting caught in gear or in between your legs, also you can push with it and not just pull, meaning that you can push your rope or rigging line into a position or crotch.
Also you can put the hook under your line and when you lift it up, the hook does not turn which if it did turn would release your line making you very frustrated, as I have experienced so many times with Sherrill's Reach tool.
It even has a little bit of Velcro on the outside of the hook allowing you to push the rope without it sliding off, which is very neat because you never know which way you may need to move your rope.
A good example was when I had to put a loop over the outer tip of a limb with my rigging line to form a spider balancer and I simply could not do it in any way with the Sherrill Reach tool because the hook would spin and release my loop, whereas with the Sidekick it was a cinch(no Pun intended). This was critical, because I could not climb out to the end of the limb and yet had to get the job done to earn a day's wage.
The hook is smaller and unbendable, but is perfect for what we will be doing with it, and that is, placement or removal of lines and small objects.
Anyway, for the money, Sidekick's the way to go. And maybe one of you innovative mechanically inclined guys can make it better.
Safe climbin.
Charlie Brown.