The guys over at smokingmeatforums.com are constantly talking about there PID controllers for keeping exact temp remotely.That stuff looks amazing!. I have never heard of Flameboss but have considered other brands. I have had so much bad luck with remote thermometers that I hesitate to spend a bunch of $ on a system like that.
I bought this bluetooth thermometer and seems very accurate with 6 probes, it tested dead on at 212 in boiling water.
https://www.amazon.com/gp/product/B07NW9GSC2/?tag=wranglerorg-20