I would think about what fits your personal situation, and who would write the strongest, most thoughtful recommendation.
This is spot on. Think of the application as one cohesive story. Which areas are well-addressed by the rest of your application? Which need a boost? I used my 2nd rec to highlight some educational opportunities I'd pursued after undergraduate, because my academic record was less than amazing. If you need to highlight being a rockstar at work or your extracurricular pursuits, choose accordingly.