Our incubator is Rite Farm Products' Model #3600 Complete Pro Digital Incubator Kit. It was just under $100 and has proved to be pretty reliable. I do use an additional thermometer and hygrometer to make sure my levels are just right.
One of our first bigger hatches was a combination hatch with quail, chicken, and duck eggs. We had decent results, but it was difficult to give the ducks as much moisture as they needed, without drowning the other eggs. Check out the video on that hatch:
Here lately though, I've been sticking to just uncubating quail, and I generally get
around a 70% hatch rate with them.