has anyone tried one of these for linking stereos?

the wife got me a fm transmitter for v day and just wonding if anyone has tried using them. ive looked the trasmitter up and it seems pretty legit. just wondering if there is much lag time between my system and the ones im broadcasting to. the model she got me was a fs czh-05b seems like a lot easier ways to link stereos besides just jumping 420 to 420. ive heard wetsounds is coming up with something, what are they planning?