R7 is the best currently, especially when price is factored in. However, it was so chatty that I only kept mine about 4 months and I sold it. Great range, but just too sensitive to junk.
Whatever you do, Waze is a requirement. Waze by itself is an ok solution, but Waze with even a mediocre detector is a really good system.
If you want a game changing approach that will make all other detectors obsolete, Google Radenso Theia and start saving your money. Zero false beeps isn't going to be a hollow promise for these guys, this is a paradigm shift in radar detection using the type of logic and strategy our electronic warfare industry has been using for decades.
My opinion, if you are going to spend $300 - $400 on an R7, just buy once / cry one and spend $800 on Theia, because that R7 will beep so much that you'll stop trusting it, which is a dangerous situation where speeding fines are concerned.