Thanks, John and Smolt -- I was pretty sure the strong yeasty smell and taste were not quite right, though all I have to compare to is store-bought Kefir. As for procedure, I added 1 cup of milk to the grains (that's the amount called for in the instructions), let it sit 24 hours, and then strained. Initially not very much happened in 24 hours, although even then the dominant smell and taste was of yeast, but after two or three batches, I started getting the extreme separation.
Smolt, you say that you leave it until you see whey in the bottom of the jar -- do you get a lot of separation of whey and curds? Do you just stir it back together, or ... ? When I have tried to stir the separated product back together, I get a grainy texture ... along with the yeastiness!
Based on what you all are saying, I'm thinking I need to try again with a different batch of starter grains. Interesting that you both got grains from eBay -- I hadn't thought about that avenue ...