Bad: the reasoning. They literally weaselled out of ruling on actual data and the implications of collecting it, instead ruling on the fact that TO collect the data, the tracker must be placed on your or your property, which would be trespassing. This makes the ruling useless precedent-wise, and gives the government a simple hurdle to jump over - find a way to attach tracker to person/device that the SCOTUS would not find to be a trespass. This is similar to the earlier case (which they ruled the same on for the same treason) UNITED STATES v. JONES ( http://www.supremecourt.gov/opinions/11pdf/10-1259.pdf )
I really wish they'd collect their balls, and actually rule on the real issue at hand. They even mention in the USA v Jones case that they realize that they will eventually have to. See page 32. They clearly understand what is at hand and why it is important. Just do it already!