Best practice is layering and being aware. Relying on a single countermeasure is a good way to fail and end up with a ticket.
Agreed. I bought an Escort 9500ix some time ago and didn't get a ticket for nearly a year until I was blazing down the road like a retard and a cop on his bike not only saw me flying by everyone else, but had also hit me with his laser and I couldn't slow down in time. Then I find out laser shifters are completely legal in Texas so now I need to buy one of those. I usually don't go much over the speed limit (usually 10 over in town, 20 highway) but I've come to feel comfortable driving faster. In light of the various safety videos and anti-texting campaigns as of late, the last thing I want to be doing is driving the speed limit next to someone who is texting so he or she can slam into me. Plus this allows me some space and I can foolishly text and drive myself if I feel inclined. Point is that a comfortable driver is a safer driver, so if going 10mph over gets me a ticket every so often, so be it. Slowing down is not an option for me.
As for the app the OP speaks of, it sounds a little sketchy. I kind of doubt with all the expensive detectors, shifters, blockers, etc... there is just some cheap little app in the market that puts them all to shame.