When I moved into my current house I repainted the entire thing(ceilings, walls, and trim). I primed and did two tops coats. Took forever, well not really forever, but painting is so boring. anyway you can imagine since the trim was the last to get top coat I thought about leaving it just primed. It looks a thousand times better with paint on it. Also the kilz has a kind of rough finish to it where paint ends up being more smooth. I would paint it myself. If you want really bright white,I used Behr ultra bright white for my trim and it is really white, will definitely brighten the space up. I also found that after time color starts to bleed through the primer, but disappear when top coated. Just my thoughts.