What is more important from your point of view? More Twitter Followers or More Twitter exposure (more messages containing your keywords and/or links)
Example: We have 2 different Twitter acounts. Firrst has 5.000 Followers and sends a message with a link, once. The 2nd account has only 500 followers but posts the same link in different messages 10 times a day. Witch one will produce more traffic to your site?