Yes, I do use the Unicender and can't imagine working without it now. Whether it is a good choice for you or not, will depend on what you plan on doing with it. If it is just to replace a hand ascender for footlocking, I would say it is not worth it. If you are going to use it for doubled rope work positioning, I would also say it is not worth it.
If you plan on delving into SRT and work positioning, then absolutely. Most versatile tool for this type of tree work available at the moment. But be forewarned, I had an awful lot of hours on doubled rope climbing and work positioning. It took me forever to get comfortable with and utilize single rope technique in work positioning. Not the Unicender, but the single rope technique itself. The Unicender itself is pretty uncomplicated and easy to use.
SRT entry and work positioning is totally different than doubled rope and requires a different thought process for moving through the trees. I use SRT now on virtually all tree work, even the small stuff.
Dave