I have had both buds, and here is my honnest opinion on both of them.
Sound: Both buds sound great. They sound really good. But the buds3 fe sounds a bit better and has a deeper bass then the buds fe. But there is not a huge difference in my opinion.
Anc: Although the buds FE have good anc, the budse FE anc is way better. The Buds fe is good for backround sound that is the sale bassicly all the time but its not great for sounds that just happen quickly. The buds3 FE has is way better at sounds that happens quickly and a bit better too at backround sound.
Batterie: The buds FE and Buds3 FE has the same batterie but the case of the buds3 fe is a bit better.
Design: The buds FE has no stem while the buds3 FE has a stem.
Comfort: The buds FE are niccer to have. They are lighter and they just sit there and you forget they are there while the Buds3 FE are more heavy and is just not has nice to wear.
Touch feature: Both have a button for pause and other stuff but the buds3 FE has a stem that adds volume control while the buds FE does not have it.
Case: Buds FE case is really shiny, flat and a fingerprint magnet while the other one is less of a fingerprint magnet.
Durability: Buds FE has not water resistance while the Buds3 fe has IP54 water and dust resistance. I want to add that one of my buds FE stoped working and thats why i bought the buds3 FE.
Conclusion: I recommend the buds3 FE because its just better in almost everywere but i
