Isolation: As ear “filter” rather than plugs, the Dubs are ventilated and don’t feel like they are creating a seal with the ear canal. As such, they are appropriate for use when at a concert hall or cinema, as the sound is not muffled, due to all frequencies being blocked more equally than the other options. Both the foam earplugs and the Etymotic Mc5 with foam Monster Supertips muffle things, especially treble, and are more suitable when silence or more protection are desired. The Dubs ear filters are the only item I wouldn’t use for gun hearing protection. Etymotic earphones and foam plugs seem to isolate well enough.
(Note: Some people thing that large headphone style hearing protection inherently works better to protect the ear because it’s bigger. This is not the case. 3/4″ of foam in the ear canal is effectively going to do the same thing acoustically as a large layer of foam of equal thickness surrounding the ear.)
Comfort: Foam is the most comfortable most of the time. The Dubs however are so light and press so little compared to the expanding foam, that short term they feel more comfortable. Eytmotic earphones aren’t known for comfort, though for a few hours, they work well enough after the foam has softened from body heat.
Sleeping: Things sticking out of the ear at night can acoustically transmit sound to the ear canal if brushed across fabric, a pillow, etc. Foam lessens this, and has much less risk of falling out.
Cost: Earphones are electronic, while the other items are single use and passive. If you have an effective noise isolating earphone without ports on it, and don’t plan on using it to block noise while sleeping or at a cinema/performance, there is little need to purchase an additional kind of hearing protection.
Visibility: When properly inserted, foam earplugs should be mostly inside the users ear, and not visible to others looking at them straight on. Even deeper insertion where the end is covered by the tragus is possible, depending on how well it it compressed, and how large and deep one’s ear canals are.
Compact: Foam earplugs come in individual packages and can be put in a pocket with anything else without worry. The Dubs are the least compact in a hard, thicker case, and Etymotic earphones in a flexible, thinner package are more easily pocket-able and retrievable overall than either of the other two items.