I have been a satisfied user of Tiles for several years now. Have had them on car keys and other things that MUST NOT get away.
Have on several occasions found things in "impossible" places where I would normally not have looked.
However, have been hesitant to recommend them since the previous model navarit once and lasted about a year. With the new model it is possible to replace the battery so now I can highly recommend them.
Have tried both this and the Pro variant. What I noticed as the biggest difference is that this model more easily gets the sound "choked" (significantly lower) if it lies flat with the back to something.