This is a very good question. During various consulting engagements I have directed my clients in both directions. Assuming the quality of the customers are all equal the ideal situation would be diversified between both types of projects. This keeps you from having too many eggs in a single basket or doing so many projects that you may not be doing your best work. The personal solution for you lies in the bandwidth you and your team have. If you are financially stable enough and have the bandwidth to take on larger more lucrative projects you can add them to your product mix. If you are starting or have a tight cash position I would direct you to take on more of a rapid fire approach. In the end you are building a brand (either for yourself or your company) so please make sure the level of competence and professionalism are high.