I would say that there is a big difference and definitely worth the upgrade.

However, my purely personal view is that “spaciial audio” is not all it’s cracked up to be.  For music listening I would rather have any of the following Sonos speakers than a single ERA 300, for similar or lower cost:

A single Five

A single Play:5 gen 2 (pre owned)

A pair of Play 5 gen 2s (would probably cost a bit more than a single new Era 300 though)

A pair of Era 100s,

A pair of Sonos Ones or One SLs

I doubt that everyone will agree with me!

Thanks John. In your experience then, does the Five sound better than the Era 300?

Interested in other people’s views too!

I haven’t heard the 300 in a good listening space but from the comments here by multiple folks I’m not sure I’d want a single one for music playback.

I do most of my listening to a single Play 5 and an quite satisfied with it. I have very limited space available but if I had to pick another single Sonos to replace it that would be a Era 100, followed by a One. Either of these in Stereo Pairs will give you a lot better imaging than a single Five/5 but probably a bit weaker low end. A pair of 100/One and a mini-Sub looks like an attractive alternative to a pair of Fives.

The difference in my Play 3s and my Play Five is huge. The difference in the Play 3 and a One SL isn’t as big but when listening to them Grouped it becomes clear that they sound a good deal different. My ears aren’t great but when I sit between the two and have them as balanced as possible in volume the apparent location of the sound moves between the two due to what seems to me to be different frequency response. I see the same in the 5 - 3 Grouping but not in the One 5 grouping.

“Better” is very subjective.  I would say that the Five has a slightly richer, warmer sound, and better bass.  Actually, I have Play:5s (gen 2) not Fives, but I have heard the Fives at a cousin’s house, and they seemed very similar to me.

Possible advantages of the Era 300 over a Five include::

1Built in voice control, including SVC (although a cheap 2nd or 3rd gen Echo Dot can be used to add Alexa to the Five or Play:5)

2 Spacial audio (eg Atmos)

3 Bluetooth

Anyway, both speakers are very good.  I prefer the Play:5. for music