Sonos’ own opinion is 2xFives is best for stereo music listening. 
That said, I don’t think you’d be disappointed by the 100/Sub Mini setup. 
If there’s nowhere local to you to audition them, choose a configuration and home-trial them. Sonos offers this in most/all regions. If you don’t like the sound return them for refund and get the other. 

Sub option in my view. Especially because it allows the music to sound rich at lowish volumes by retaining the bass lines better than a stereo pair ff any model does. And it lets the main speakers sound better in a subtle way by relieving their drivers from also delivering bass lines.

PS: try both as suggested, but if that is unwieldy to do, trial the sub option first.

I've been listening to Fives side by side with a pair of 300s and a Sub.   If sound quality is the only consideration, I'd go with the Fives.   They have nice bass and mids and don't require a Sub.   I imagine that they would do even better when stacked against the 100s and Sub. 

That said, sound quality doesn't have to be the only consideration.   How well they fit into your room's decor or space can matter as well.  You can count on the 100s and Sub to sound very good and if they fit the space better you won't be disappointed. 

Fives. Best stereo image with none of the (usually very minor) localization/image drawbacks of a Sub.

Thanks for your suggestions. Because I bought through Sonos, I had 100 days to test them. Based on your advice I tried them side by side.

My conclusion and advice for anyone else considering the same options:

The Era 100’s with the sub-mini are a solid performer that offer bass that many people will be happy with. Not a bad set up at all. However:

The Sonos Five’s blew these out of the water. I was expecting the Five’s to be a LOT more bass-y to be honest, but after setting up True Play on both, the sound from the Five’s had far better clarity across all ranges from low-mid-high, the speaker seems to be so much more sure of itself. Not quite as bass heavy, but easily enough to add the bass I wanted through the equaliser.

As I said, I am mostly using these for vinyl and I really enjoy the sound the Five’s produce and can see myself chilling and relaxing with some quality listening sessions with these, I do not think the Era 100’s with a sub-mini match these in this scenario.

As much of a fun and brilliant speaker the Era 100’s are, they are being packed up and being sent back with the sub-mini in favour of the brilliant (although slightly more dated Fives).

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Disclaimer: I still have a Beam 2, with 2x One and Sub Mini, which for home cinema in a sensible sized room is outstanding and a set up I love, but this post is for purely listening to stereo music in mind.

Hi @Mackstar 

Your decision to go with the Five’s over the Era 100’s and sub-mini is spot on .  The Five is still the Sonos flagship for stereo hi-fi listening.  I would have been very surprised if you had decided otherwise. I may have suggested you visit an ENT (Ear Nose and Throat physician) 

Enjoy your Sonos listening!

I bought this setup, two era 100 and a sub mini. Came from two Play 5 (1.Gen). I am disappointed. The sound is not bad but is just not as full as the sound from the Play 5’s. It sounds just like the the eara 100 looks - small. I’ll return them, but don’t know if I’m going to buy som five, era 300 or a Port and use it with my old Klipsch R-15PM speakers.