I have both PLCBUS and Z-Wave running (I'm in brisbane). If the PLCBUS devices are turned on or off from a wall switch, then they won't transmit anything to say that the light has turned on or off. I had to modify the PLCBUS GSD code to poll the devices using the GET_ON_ID command which then updated LMCE with the lights that were on and off. Having said that, some of my PLCBUS units didn't respond to it at all and all the lights pulsed every time the command was sent, so I only had it going every 5 min. If you install the PLCBUS scene controllers, then they are sending out a signal whenever the switch is turned on or off, but then you don't have local dimming by holding the switch down (with momentary switches). It means you then need the scene controllers for the switches and the lighting module for the lights. I have used a couple of momentary switches to get local dimming and a couple of scene controllers. The rest are just wired into standard on/off rocker switches.
Z-Wave on the other hand will notify LMCE when a device has turned on and off locally, so the change is reflected in a few seconds on the orbiter. Which makes it much better for setting up events in LMCE.
I am in the process of changing over to Z-Wave because I seem to have a strong ripple control signal at my place (the signal energex sends out to turn tariff relays on and off among other things) so my lights flickered (more of a strobe really) quite badly whenever the signal comes through, which was on the hour almost every hour and sometimes on the half hour. Occasionally it would even turn a light on or off...doesn't exactly help the WAF. Not sure if that would be an issue for you, but you might want to test a lighting controller out before filling your house with them. My Z-Wave lights only flicker when they are dimmed below about 70% and not nearly as badly as the PLCBUS devices.
It is a shame that Z-Wave is so sparse in Oz at the moment. As far as I know, smarthome are the only ones selling...and not cheaply either. I'm waiting for a few more modules to come out here before I go over completely. Like scene controllers and motion detectors.
PLCBUS did have some features that I liked, like being able to set the fade rate on the fly, All Lights/Units On and Off, multiple scene addresses per module, etc.
One slight difference with the way the switches work (normal switches, not momentary switches). With PLCBUS, change the state of the switch and the light will change. So if the switch is in the Off position and the light is On, turning the switch On will turn the light Off. Which is what they said in the reply, but this DOESN'T send a signal out to say that the light has gone on or off, so LMCE won't know about it. With Z-Wave, if the switch is Off and the light is On, turning the switch on will do nothing, but a signal is always sent out so LMCE will know that the switch was switched.