The best custard flavor I have found is from Capella, I don't like the one from One on One at all. It has a strange taste to it. Almost peppery. One on One's cereal flavors are great. I have Fruity Pebbles, Apple Jax, Fruit Loops, Rice Krispy and Captain Crunch. I find that a touch of marshmallow added to the RK tastes just like RK treats. And adding a bit of peanut butter to captain crunch also works quite well.
There tobacco flavors are also pretty good. Their cinnamon roll is outstanding! As is their rainbow sherbet (hasn't been in stock for quite some time though), creamy caramel candy and cake batter.