I also had a playbar-Sub gen2 and 2xPlay1 before I decided to upgrade.
Initially I bought an Ultra and had it set up with my Sub.
The sound may not be quite as powerful as on my playbar but much more detailed, I can easily hear the sound spreading much better than on my playbar.

Depending on your settings and placement of the ultra, you should experience the sound embracing the room much more. However, you will only experience real Atmos when you install a Sub and surround speakers.

I have just had the Era300 installed, it is a completely different world and can only recommend that you buy surround speakers. You will only experience the deep bass if you connect a Sub, the ultra delivers a nice bass but for me it is clear that a Sub is missing.

Many thanks for your reply Peter. I do already have a sub and it’s connected. I’ve tried to be realistic in my expectations because I planned to add rears later (although I know 300s would be better, probably cannot justify those in our room setup).

Without doing a side-by-side with Playbar, it’s hard to tell the difference but I expected at least some level of surround experience, otherwise why justify the purchase of Arc standalone at all?

I am faced with every guys nightmare - my partner is questioning my tech choices because she cannot hear any of the promised surround effects either. I’m never gonna be allowed to buy any tech again! 

I feel that ARC ULTRA offers more detail, but you need actual surround speakers for the full effect. Ultimately, ARC ULTRA and 300’s will give full ATMOS. In the short term, returning the ARC ULTRA and adding a pair of 100’s will be a step up — and relax the domestic situation.

What settings have you set on Ultra and if any on your Sub?

I would buy Era300 especially now that there is a 20% discount on it.
(Remember you have a 30-day full return policy)
It is ONLY with Era300 that you will achieve the full Atmos effect.

I had Play1 before and they also worked fine, would be similar to Era100 (however Era100 is a little better than Play1)

Hehe I'm picturing the conversation "the good news sweetie is that it will only take another £718 to hear a difference we thought we were gonna get"! Classic case do I invest more or cut my losses and return the Arc. 

Just really disappointed and I've been a Sonos fan for a while.

Thanks for the replies!

I’m having the exact same issues with my new Arc Ultra and sub 4, not spatial sounds at all. Also after true play the bass is suboptimal and voice enhancement doesn't work. Have you found a fix by now? 

 I would not expect miracles from a soundbar from any brand.  Don’t know your room dimensions or configuration.  The side and height speakers work best in a symmetric room with reflective wall & ceiling surfaces.  If there is an open space on one side of the room or if you have a vaulted ceiling the performance of the soundbar will be compromised.

 My room is exactly as described above.  After adding a pair of Era 300s the sound improved greatly.  
 

 Since I don’t know the configuration of your room I don’t know if surrounds would work that well for you.  The best results would be with the surrounds behind you maybe 4 or 5 feet away from the listening position.  They work best on stands at ear height.  Of course most people can’t do that in a room that serves other functions.  Maybe your lucky and have the ability to set them up that way.

 If you do decide to set up surrounds with the Arc Ultra run Quick Tuning TruePlay rather than Advanced Tuning TruePlay as there seems to be issues with bass loss with the Advanced version.  Make sure the microphones are on for the Arc & 300s before performing Quick Tuning.

I took the leap and brought two Era 300s (used the money saved by my partner leaving me for a Bose owner). Black Friday discount sealed the deal. Plan to set up this weekend so will report back my findings.

Some great ideas above around setup and I’ll give the Quick Tuning a go (interesting I HAD noticed bass was a little lacking in Arc and increased sub output as a result - maybe a result of that tuning issue??).

My room is largely standard rectangle except my TV is placed more toward one end. So area to right of it (as I face it) is greater than left and I wasn’t sure if tuning into that area or only the half of the room I’m actually sitting was what I should do, so tried both but did not notice much difference. Welcome any advice on this point as I’m sure many people do not have perfect shaped rooms?

So in summary, going with the rear speakers sooner than expected. Accepting (because I am pragmatic) that placement not ideal because sofa is nearly against wall. If a moderate revelation is not forthcoming, gonna return them and probably sell Arc 

Oh, just one thing to add to above. I HAVE noticed an improvement in speech with Arc Ultra over Playbar. I have it set to medium setting and can say that speech seems clearer and more distinct.

Considering this is two generations on however, hardly a surprise (sorry, I sound disgruntled but am just heartily sick of all the YopuTube headlines declaring the Arc - alone - is a revelation and feeling I must be missing something).

This might be why it’s not as immersive for me. 
My ceiling is approximately 8 feet high. I sit about 13 feet away from the Arc. On one side, there’s a glass sliding door with curtains in front of it. On the other side, the space is open toward the kitchen.I’ll probably get the 300’s at some point, although my couch is against the wall. 
Still don’t get why I’m not hearing any speech enhancement effects though.

I would love to hear back from you, if it helps I might add the 300’s sooner than expected as well. Also my couch is against the wall so I’m wondering how much that will affect the sound.

How high does your Arc sit from the floor?  Mine is sitting on top of a fireplace mantle, and I found that tilting the Arc slightly forward (and old 1 cm book placed at the back end) directed the front spacing speakers towards my couch better as well as improved the angle on the height speakers.  You may want to experiment that.  Alternatively, you could place a chair around 8-10 feet from the TV and see if you feel the audio is better.  Depending on how you value the aesthetics of the room vs the sound quality, it may be worth rearraigning the furniture.

As far as the sides, I don’t think there is much help there.  curtains are not reflective for audio, and neither is empty space.  I think you will fine rear surround speakers help out tremendously though.

edit: Wanted to add too that don’t feel like you need to get Era 300s for surrounds.  You certainly can get Era100s  and see a big improvement if cost is an issue.  I’m still using Sonos Ones with no plans to upgrade anytime soon.