I'm just about to start my first round of facebook ads for my b2b startup. I was wondering what worked best for you? I read your post and you mentioned users from sources such as Google... what else worked for you?
Don't bother with FB. It's a waste of money for B2B.
Nothing is guaranteed to work. AdWords could be a great way to jumpstart customer acquisition, or a great way to waste money.
The important thing is to _experiment_ and _evaluate_ (using analytics and attribution tracking) because what worked for one company might not work for you, and as a startup you often can't afford to blow $20k just to learn that lesson.
(Speaking from experience. I'm a b2b marketing consultant and I've been through this many times.)
Just like with everything else, if you have the time and skills to do it yourself, then no. Otherwise yes, get help. If you know exactly what needs to be done and how, then hire a freelance specialist. If you know something needs to be done but not sure what or how, then hire a consultant.