That's kinda like asking about Coke vs Pepsi, Chevy vs Ford, etc.
I have Z-Wave stuff and really like it. I very rarely have something you'd classify as 'unreliable.' In fact, I may not have ever (knock on wood)
I have some GE plug in modules and some GE switches with no problems. I've only been into this for a year or two, so I can't attest to their longveity.
You also need to think about controllers for this. I liked the MiCasaVerde Veras, and it is predominately a Z-Wave device. Guys use Insteon with it, but not as much. Or maybe you want a PC based thing which opens more doors. Or maybe you want nothing and just want to program everything manually with remotes!
I'll be using a PC running some sort of home automation software to control this with Android tablets and phones. I have some custom sensors interface and HVAC controls that I am designing and will integrate into the same system. I'm in the early stages of deciding exactly what I want it to all do.