I used vanilla in a Chocolate Oatmeal Porter I constructed a few weeks back. Decided to buy 2 beans, and toss them in secondary.
I split, scraped, and chopped up the bean, put it in a dish and used some bourbon to meld it all together. The caviar from the bean was sticky and all over the place, the fluid made it a bit easier to wrangle and get all in the container.
I didn't have much in there, but dumped it all in the beer after 2.5 weeks in primary.
I have a nice subtle, but CLEAN vanilla finish to the beer that keeps it balanced.