Hi, 

The answer for if it matters which you use is mostly no. They will all break down and add nutrients to the soil as they decompose. However, there are some considerations: 

• Where is the mulch coming from? A lot of shredded hardwood mulch is supplemented with wood scraps and this is sometimes pallet wood or wood that has been treated. If the landscaper is using a local mulch company that makes its own product, then you could check and see what they use. 
• We would recommend to not using dyed mulch. There isn't any scientific evidence that the dye can harm the environment, but if the purpose is to condition the soil, then it would be best not to have added unnatural ingredients.
• Where is the mulch going to be located? - If it is on a slope, then the larger pine bark mulch can wash away easily with heavy rains.
• How quickly do you want it to decompose, and are you willing to top dress the area with more mulch often? The smaller the pieces, the quicker it will break down.
• Are you trying to let some plants reseed to spread? It can be difficult for seeds to work their way down through the larger pine bark; alternatively, this may be beneficial for any weed seeds that migrate into the area. 
• If you need to condition soil with amendments, we recommend using compost or very finely shredded pine mulch material to mix into the existing soil. This depends on the type of plants you are planting (the species and how it's prepared, i.e., in a container, bare root, or balled and burlap). - Nursery plant growers often use pine fines or a mix of pine fines and potting soil to grow plants in a well-draining medium but they are fertilizing often to replace nutrients that are being leached out. Mixing pine fines in with existing soil can cause the immediate area to drain too quickly and the newly planted plant to dry out quickly.
• Pine bark versus pine straw versus a mixed shredded hardwood will not significantly alter the pH of the soil, so the type of mulch doesn't need to be chosen for that purpose.
• The thickness of how the mulch is applied is important. You want it about 2-4 inches thick and pulled away from the trunk of trees and shrubs by about a 3-inch circumference (no mulch volcanoes). It may take more pine straw to accomplish this than a larger bark nugget mulch.

Let us know if you have further questions. 

Emily