Anyone tried the cheap V4 or V5 1200m intercoms?

They look useful for an upcoming off road bike trip for communicating as full duplex for 4 riders. Has anyone bought them? Obviously not expecting Sena quality, but they're only £185 for a set of 4 of the V4.

I've used the v4 interphone paired with one other rider. It worked well for us at up 50mph on road bikes, at 60mph and upwards although it was working it was hard to hear over the helmet noise. How you'd get on with a Dirtbike and 4 riders I don't know. On the road the only physical obstacles between bikes were lorries. If you were riding in the woods physical obstacles might be an issue. My mate thinks that one of his units failed whilst he was riding for several hours in torrential rain. My Arai Chaser V does not like the mount for the V4 and I have broken a couple of mounts, something about the angle seems to sprain the mount, the TourX does not seem to damage it and my mate's Shoei Neotec is fine. The earpieces are uncomfortable on a long ride in the Chaser V, The TourX is fine. The buttons on the side of the unit of the V4 are nigh on impossible for me to use accurately once the lid is on my head so get everything paired up pre ride. The V5 looks better in this respect. The low price of the V4 is a major attraction, especially for off road.

Thanks for the information. Looks like it may be worth going for the V5 for the half decent buttons.