​@csarvind 

Assuming you mean Sub gen 4? 

You will notice a difference. BUT it entirely depends on the space you’re trying to fill with sound. A big room might benefit the Era 300s. But a smaller room is fine with Era 100s. The 300s are also bigger so it depends what space you have and whether their placement behind someone might overwhelm them.

Sonos has a generous returns policy. If you’re within the timeframe, buy the 300’s and try them out. Return the ones you don’t like so much - or set them up in another room. 

The Sonos Era 100 is a compact smart speaker delivering impressive stereo sound and deep bass, ideal for small to medium room.

Reviews rate it as a major sound upgrade over the Sons One: punchier bass, real stereo imaging via dual angled tweeters, and rich mid-range clarity Audiolab+13WIRED+13gq.com+13. It scores top marks for sound, features, and build quality , and is frequently cited as Sonos’s best compact speaker to date Coast Guard Exchange+12The Guardian+12techradar.com+12.

In short: the Era 100 is portable, easy to set up, eco-conscious, and packs premium, room-filling sound from a sleek, bookshelf-friendly footprint.

A lot comes down to speaker placement if properly set the 300s are noticeably better, even more so on Atmos content.

If you can't properly place them you might find (as I did) that the 100s sound about as good.

I put my 300s in another room as a stereo / Atmos pair and love the sound.