I use the Nivek system that we ordered from KWcages. At first we bought the tubing, but when we buy more, we just goto Home Depot and get the clear tubing, but the black tubing works wellsince it doesn't allowalgaeand mold to get in, since it's black. It was cheap toget, and easy to install, and has worked well besides the two problemswe've had with it.
The problem we had with it is that it lets out to much water, and thecages would be soaked, so we had to make a drip system... and we thengot rid of the drip system, and are currently using the old feeder cupunderneath, but the pigs tend to move the cups. We are still trying tofind a good drip system.
The other problem we have is were it tends to leak, and when they drinkout if the sipper, the water goes backwards also, and gets all over thefloor, and goes to other cages, and gets them wet!
But I love it, hence those annoying problems, since I just have to filla few buckets up each day or so, rather than those annoying waterbottles. And it's tons easier to clean than the water bottles, anddoesn't need to be cleaned as much. Plus it doesn't make the annoyingnoise when they drink from it, like water bottles do.
I still have a cage tower that still has water bottles for now. We areswitching two of our towers to wire instead of Creative Cubes, so I'mnot doing any new watering system hook up for the tower with waterbottles, since the design will be switching for both towers.