I bought all three thru Rock Sky Market so they handled all returns. If you've never purchased anything from RSM, do it. They are phenomenal but because of that, I have never dealt specifically with L&B's customer service although I have only heard good things about them.
All of the malfunctions happened at different times during a typical skydive: First time= immediately after exit. Viso read 14.4 when I left the plane but first check showed 0 and buttons didn't work. Second= landed, picked up chute, walking back to the hangar and started hearing a beeping sound. Alti worked fine for free fall and canopy descent but heading back inside pissed it off. Third= Cessna ride up, glanced at it during take off, display was normal (always takes a couple seconds to start reading), after a couple minutes I looked again and the time/date disappeared and the dash that separates the hours and minutes was blinking, buttons didn't work. Stayed that way thru free fall and canopy. Sent it back just like that so RSM could see what was going on. My L&B audible was with me for all three jumps and works perfectly.
I *really* want to give a Viso one more try but I'll feel like an idiot if the fourth one mucks up (how many times will it take me to learn my lesson??).
Definitely don't want to go back to the analog brick either...