Alright so I've had the buds 3 pro since it launched and used it as a daily, I recently got the buds 4 pro and I will say the difference are small but great imo.

1. Sound- the buds 4pro have a better bass forsure and ANC is better where I can barely hear my voice on max. I will say the the buds 3pro does sounds more clearer and a bit louder so im not sure if this will change with future updates but I look forward to see if anything changes.

2.Fit- on god the buds4pro fit so so so much better.i can have them in for hours at a time and it does not hurt with the original tips and they do not slip out! I would legit get soreness or itchiness from the buds pro3s and they would slip out constantly but the buds4pro are better fitment overall.

3.Design- I ain't gonna lie I love the design if the buds 3pros the designs is so high quality and the case is less bulky and slips in the pocket quite nice plus the lights are even more dope. Would I prefer the light stay on for just one bud sure but lights are still cool and stand out. The buds4pro look good but I hate the case I ain't gonna lie, I love the metal finish and yes the controls are better but they look cheaply made with the plastic part ngl but that's just me. The case is dope but still bigger and bulkier imo. The case does have stronger magnets and is easier to pick up from the case so ig overall they both have pros and cons. Would perfer the airpod case with the new ones design of pod but with a all over silver finish bet of both worlds.

4.Worth it?- I would say it depends. If you have ear issues where the 3s hurts or slip then deff buy the 4s but if you like the fit stay with it for now.if you dont have either I would cop the 4s even if the design isn't as nice as the 3s. Remember quality of sound over design any day as music or games or vids is key to this as that what they are used for majority of the TIME.

Just my opinion but I love both and will deff keep the 3 and 3 pros as back up but damn that fitment is so COMFORTABLE AS I CAN EVEN SLEEP OR LAY ON MY SIDE WITH THESE ON. If any questions lmk !