Strengths: Did perform well for almost 6 months.
Weaknesses: The shadow plus spring stopped functioning after around 6 months, so now it is as good as a shadow without the plus.
Maybe tension is even a little less than the tension of an ordinary derailleur.
Not much to say that is not mentioned above.
While the shadow plus spring was OK it was great, thereafter not so great.
Next try will be a XT shadow plus as I do not like the noise that comes with the SRAM shifting system.