this is my own opinion, which others may not share, but FWIW:
Soft (104 COE) is popular for beads:
- huge color palette
- relatively low cost compared to boro
- relatively lower heat required to melt compared to boro. This also has implications on what kind of equipment you need, as well as your personal tolerance for heat on your own skin (much less radiated heat on your hands, chest and face).
- longer working time (stays molten longer to give more time to shape the glass into chosen form)
Boro (33 COE) is popular for sculpture and functional (pipes):
- can tolerate a lot more thermal stress before cracking than soft, so it's easier to create a larger sculptural piece
- for reason above, it's easier to work hollow forms with boro
- many available "Striking" colors which can give a very unique look based on how it's worked
many people work with both (or more COE's), but you MUST be careful about keeping them separate and well labeled. It can be impossible to tell what glass is what or even distinguish between certain colors if they have no labels. There are many stories of someone picking up the wrong rod and accidentally mixing COE's, which seems fine when everything is molten, but cracks to splinters after it cools down. So the moral of the story is: if you have multiple COE's in your workspace, you have a higher risk of mixing them accidentally and must take precautions to prevent such from happening (like only working with only one COE at a time and clearing the bench before switching, labeling religiously, etc).