I bought it on Black Friday 2023. After about 10 days connected to my Samsung QE65QN90AA TV, I have the following to say:

It is a very unique product that is targeted towards very few people. Considering that it is the most powerful and capable soundbar without additional speakers and bass - for this price, you could get a regular "ready-made" 5.1 Dolby Atmos system with multiple speakers and achieve better surround sound, although not better sound quality. It is definitely better than the options from Samsung, LG, and Sonos Arc, which cost around 1000 euros (I haven't heard the Ambeo Plus). It is what you would expect from a high-quality Sennheiser product in terms of materials, sound clarity, and bass. I don't think Sennheiser should have released small speakers to complement the mediocre surround sound of the soundbar - like other companies have done - as I believe the Ambeo Max achieves what it aims for: maximum quality in a "small" speaker package. The seriousness of the company's purpose is evident from the special microphone included for calibration.

HOWEVER. For its price and what it offers, I have the following to say:
-The DTS:X in 10-channel sound from Blu-ray is fantastic.
-The Atmos from 5.1 or 7.1 from Blu-ray or downloaded movies is okay.
-YouTube and other music streaming services like Tidal don't have multi-channel sound, but the Ambeo profiles do a great job of adding volume and dimension to the sound.
-And here is the big drawback: if you will only be using Netflix and other streaming services, then it doesn't make sense to get such a good soundbar because you won't be using it to its full potential (usually, it's all Atmos 5.1 channels). If you don't give it the best possible Atmos or DTS signal, then it simply isn't worth the money. The Ambeo Plus or Sonos Arc would be more than enough for this job.

Nevertheless, the Ambeo Max is a unique product because there is nothing else that achieves better results at this price.
-Will you get a cheaper soundbar? You will lose in sound quality.
-Will you add satellite speakers to the soundbar (reaching the price of the Ambeo Max)? You will have better surround sound but not as good sound quality.
-Will you get an amplifier with two speakers at this price? You will possibly have a better soundstage, but you will lose the (even mediocre) Dolby Atmos and DTS, as well as the capabilities of an AVR (Tidal streaming, Airplay, etc.).
-Will you get an AVR amplifier (like the Denon x2800h) with two speakers at this price? You won't achieve anything better, and it will be a hassle to fit speakers in your small living room!

Edit after using it every day for 2 months:
-Depending on the sound mixing and mastering of Atmos in each series/movie, the voices don't sound as good at low volume (below 15%), and many times the music and effects drown out the dialogue (mainly because the voices are mostly coming from the center speaker, while everything else plays through all the speakers, I believe). I have tried all the options and Ambeo profiles. If you increase the volume slightly, this problem doesn't exist. There is no problem with DTS or PCM.
-There are occasional slight "cracks" and "pops" from the speakers only in Atmos. I changed the HDMI cable, and the frequency of the issue decreased.
-I am impressed with the soundbar's performance in music playback, it is really good even from YouTube.

Amazing solution. Truly exceptional experience, it changes the way you watch movies and play video games. If you have the right room, you feel like you have speakers placed behind you and on the ceiling!
I am mainly talking about the Dolby ATMOS option.
Since my TV does not support ATMOS and DTS, I connected my laptop directly to the Soundbar with HDMI 2.1 and from there with a regular HDMI 2 it goes to the TV's ARC (Samsung Q6FN55 2018). This way, the audio signal does not get downgraded! Crystal clear sound with clarity in the dialogues. Be careful, you can only change the EQ from the mobile App (which in iOS you need at least iOS 13 - it doesn't work on iPhone 6).

Well, I live in England and I live in a big room.
I didn't have space for speakers behind me, let alone on the ceiling.
It's heavy and bulky, but when you place it somewhat correctly in the room (around the center and at ear level), you add the microphone they give you to automatically adjust the sound... okay, you don't believe it... it's not for all budgets and all living rooms.
I can recommend the Sonos Arc and someone can gradually add speakers.