Great question, and not one I can answer from a Support side of things. Personally, I’ve tried out a few of them and I enjoy the upgraded quality, however, I tend to listen to music more for background noise and don’t notice the quality once it gets to 320 kbps or so. Anything past that is good enough for background noise to me, which makes HD great occasionally, but generally unneeded. 

If you do a lot of “lean in listening” where you’re really getting into the music, it’s probably a good idea to check it out. I know most services offer a trial period, you could always check it out for a month and see how you like it.

Good advice and I’d add don’t worry about any UltraHD offerings as Sonos can’t process anything greater than CD quality (which is admittedly a step up from Spotify).

Trust you ears and decide; none need more than a payment of a month’s fees, at the most.

While listening to evaluate, try to ensure that sound levels from both sources are as close to each other as you can get them to be.

Personally, I don't think it makes a difference, but that’s subjective. 

I think it depends on the setup you’re using, too. I listen to music mainly on a pair of Play 1s with a Sub and I’ve been using Deezer Hifi (FLAC) for a couple of years. I also have a Spotify Premium subscription which my teenage sons mainly use and I can definitely hear a difference. However, I wasn’t as impressed with Tidal (I had a three month trial), although I honestly don’t know why as it is also FLAC quality.

I’ve just bought a Move for use in the garden and around the house and to be honest, I can’t hear as much difference when listening to music on that. 

Sorry to pull this thread back to the top - took a bit of time to find the comment (though not all of the 3 days..).  Bit alarmed by the "background noise" purpose for Sonos identified by this Sonos man.  But the slip here does beg the question I have always had in my mind about music systems such as Sonos: are they intended, primarily, for background use (where you just hear the music) or are they (also) claiming to be able to hold their own against more 'classic' hi-fi (separates) systems?   A number of the regulars here on the forum appear to have got off the hi-fi merry-go-round (aka cash sinkhole) to be satisfied with a Sonos suite (typically a Play 5 pair and Sub).  Do these now better-off people fit the 'background noise' cadre or the 'lean-in' listeners?  And do their  Sonos set-ups really stand up to what they had before?

That’s quiet the question Brian, and I’m sure you’ll get some interesting responses from the community.

Ultimately, how someone listens to music is personal and has a lot of factors in it. Sonos as a system is designed to appeal to a lot of different people in very different types of setups. That includes heavy listeners who are seeking the artists’ intent and really enjoying every note, along with people who just want to enjoy music in every room of their home, and those who just need some music on as a soundtrack to their lives. There are several different types of Sonos speakers, and what sort of setup you have may also affect how you listen.

Keep in mind, my personal use says nothing about how Sonos systems are designed, their intended use, or how they might stand up against other systems. After all, I just work here, and not in the area where speakers are designed.

I work on the computer all day, and music is always on. But I’m focused on doing more than just listening. The fact that I have speakers which could be used for much closer listening experiences doesn’t change how I tend to listen to them, just that I really enjoy the sound. What can I say, one of the perks of working for the company is being able to use very nice speakers for an application that probably doesn’t do them justice. But this thread is about personal recommendations. Personally, I’ve tried HD services and really enjoyed the sound, but ultimately I don’t get a lot more enjoyment out of some of them. There are also plenty of people that will say the opposite, that they can’t listen to anything with lesser quality after hearing how good the HD services sound.

In my case based on experience, I would answer “both” to the first question and “yes” to the second. That is the short answer.

The long one:

From a pure technological perspective, classic HiFi systems are obsolete. Even a play 1 pair + Sub, which is the lowest price point Sonos set up that can audibly compete with these if placed with the same care as HiFi speakers, the tech is superior for offering dedicated amplifiers to each of the six drive units present, with active crossovers and DSP that can tweak the sound taking into account the all important room speaker interaction which is what you hear as the delivered sound. I also know of others here that have replaced classic HiFi with set ups like the 5 pair + Sub, and not felt compromised.

That said, the listening experience is a subjective one, and not one limited to just what the ears capture. And it is not just the eyes that are involved, there is also the impact of knowing what one has read about these separates in the “audiophile” media and elsewhere, causing biases that humans are universally susceptible to. Including the common one of knowing what one has paid for it!

A thought experiment:

Imagine you are listening late at night, with the lights turned down low, to a expensive legacy Hi Fi set up, where the dancing backlit VU meters on the imposing looking amp are visibly complemented by the glow of valves sitting on top of said amp, with substantial looking cables feeding the signal to classic looking speakers. And in extreme cases, looking like the bridge of a starship. How do you think the exact same music would now sound to you if you were to move to an acoustically identical room where the music is coming out of a barely visible, “cheap” play1/5 pair + Sub set up that however has been properly placed and true play tuned? Or, where it can be seen, with its sterile looks in comparison to the classic HiFi in the other room?

And then note that many natural biases are like conflicts of interest; they don't survive once exposed or not given a chance to come into play. Which is what would very possibly happen if you wore a blindfold and did not know which room you were in. What do you think would happen then to what you hear in each room?

The other thing to consider is why I answered “both” to your first question. That is because Sonos is so easy to use compared to classic HiFi and offers orders of magnitude more access to music than classic HiFi ever did. Of course that isn't down to just Sonos; one could wire a Echo Dot costing a lot less than Sonos to the line in jacks of your classic HiFi amp and be able to say the same thing.

On the other hand, I still have a Rega P5 and LPs in storage that I could use wired to my Connect Amp + “HiFi” speakers set up, but I can’t be bothered to now. And I have that set up only because the speakers were bought long before Sonos landed in the home in 2011, and it made sense to keep the earlier investment in use.

Trying to compare a Sonos setup to a home theater system in general isn’t really helpful as the home theater systems vary so much. My two (now gone) were good examples, the one for my office had an inexpensive Yamaha AVR, Infinity TS-455 class speakers and sub, it seems to be about the equal to my Bean, SL and Sub setup I replaced it with.

On the other hand I had a much beefier Denon AVR in the TV room feeding TSS-4000 speakers and Sub. I have a Beam and Sub in there now, not setup the surrounds yet. The Sonos setup sounds quite good for a lot of music but falls short on the lowest end as well as maximum un-distorted volume. That is something I realized and accepted and I believe a direct fallout of the number of square inches of speaker cone difference in the two systems.

Another big difference is the lack of surround options on the Sonos, full or ambient, compared to the large number of sound field options as well as the complex adjustments possible using the AVR.

I’m happy with the change, the complexity and space of the AVRs just wasn’t worth it these days.