Been using the R8 and Waze about 3 years in the Maryland area and very happy with its performance. Using the Ka segementation settings from rdforum.org for the state I live in.(
https://www.rdforum.org/threads/58040/)
Ka has saved me about half dozen times, usually from moving police cars traveling in the opposite lane towards me. I have never seen a false positive on Ka band.
K band has false positives but I find the R8 minimizes them well.
Only seen laser detection go off once. It was from a Maryland State Trooper and I was not speeding.
To the OP, the R8 has been great piece of mind for me and has paid for itself a few times over now. Everything I read about the R7 is the performance is pretty close.
Waze is great for the stationary speed traps that police like to use to maximize thier chance to catch some by using road contors or hills etc. The R8 (and others) provide the strongest protection against police using thier radar while moving. Depending on the enviorment (weather, roads are flat or hilly) I have gotten more that a mile of advanced notice that Ka band is in use.
Safe Travels!