Have you used them? What do you think of them? How should I expect to plan my budgeting process for them? (price per link?pkg of links made? ect) What pace should I plan for?
To be honest with you, I prefer to do such tasks to myself, I like to be in control of who links to me and from where, because it is never a good Idea to get a link from a non relevant source that links to a hundred other sites that don't even talk about the same thing.
My advice is that you do it the hard way, believe me in the long run it's safer and more yielding.