I've had an aquapod which is like a nanocube, for about 8 months now, I have no heater in the tank and no skimmer, and it's been doing great. and the best part I found out recently is the mechanical filtration, doesnt need replacing... just pull it out and rinse. the one negative I had with thi is, rusting of screws that hold the protective over over the lamps and fan (I would suggest adding a dab of aquarium safe silicone, and when you need to actually access the screws, simply cut away the silicone)
The other thing I've read about these nanos is that the have a tendency of cracking at the rounded edges. I've yet to experience anything like that. I think it's all about putting it somewhere with a flat surface and that won't eventually warp from the weight (avg 250-275)