The ear tips are an upgrade compared to the A20. They don't go as deep and are therefore less painful, although my ear does get sensitive after a while. I'm a side sleeper with a firm pillow, so I take them out after 2 hours.
They do seal better, and the ANC is also an improvement over the A20. Especially with music playing softly, I hear almost nothing from my neighbors anymore (stomping, loud talking). And that was the intention. Previously, I had to turn the music up louder.
They also seem to pair better with my phone, faster. I used to have trouble with that with the A20 as well.
In short, if you are hesitating between the A20 and A30, and you can get a good deal, buy the 30!