Think I've ranted about this before, but the frustrations with selling things via Marketplace and the amount of "is this still available?" messages you get, then you reply almost immediately that it is and ask if they are interested and they just never reply again. What's the point? Feel like there must be people who get some sort of enjoyment out of going through and clicking interested on everything. Or the ones who ask for extra details/measurements/photos etc so you go away and do them and then they never reply again either. "Thanks but it's not quite what I'm after" shouldn't be so hard.
Know Trademe is more reliable, but find Marketplace can be quicker and easier to deal with people directly for low value things, but of course many more time wasters too. For anything of any significant value I'd go to Trademe.