No, I'd watch BSG first. Caprica is a great show so far but there's nothing you need to know that Caprica sets up for BSG so I'd check out BSG first. I'd like to get that complete set on blu-ray! The Plan and also Razor are nice additions to the series also, which the latest set should include.
So far Caprica is shaping up to be damn good as well.
"Death, delicious strawberry flavored death!"