Zu audio

I am interested in these speakers but a little skeptical of their claims on website

10 inch driver has 11 versions of nano...

Nano materials...
Nano- sanctified..."

Who is buying this nanononsense?

I only recommend Zu if you need very high sensitivity and don’t want an industrial look (PowerSoundAudio, JTR, etc.), which is usually the case if using a tube amp. However, if you have >25W, I see no reason to look at Zu.
I have owned two pair of Zu speakers, The Union, and the Omen Bookshelf.
Both were very good for the money. The Union came close to my Vandersteen 3a sigs, but lacked the finesse.
Newer models are probably going to provide better sound reproduction, so choose wisely if you are buying used.
That being said, I think they are quite a bargain for someone on a limited budget. Of course, every manufacturer is going to tout some technical attribute of their product, so take everything you read with a grain of salt.
I have had ZuDefinition speakers for years - initially Def1.5, them Def2, and finally Def4. Each version has been a significant step forward. I take advantage of the high sensitivity to drive them with an 300b SET. Every company in every industry has its own marketing terminology and hype. Audio is no exception. I care less about the buzz words that Zu uses than about the sound. Some people love the Zu sound; some do not. I fall into the first group as does everyone who hears my rig. The new Druid VI are also really good.

Gsm18439, Can you describe the Zu sound?
I have the Zu Omen Dirty Weekend floor standers for a few months now and love them.  They replaced a pair of more expensive Opera Platea floor standers, which were in use for 8 years or so.

I made the move because I was getting bored with the sound of the Plateas.   

I am driving the Omens with a Prima Luna PL 5 tube amp and Musical Fidelity CD PRE24 preamp/ cd player.  Cables are QED Silver Anniversary.  There is also a Pro-ject Classic turntable in the mix.  I use a Parasound phono preamp with the Pro-ject.  Mostly Audioquest cables.    

Describe the sound ... here's at it.  Alive, not polite.  The Zu's are often described as speakers for rock music.  They capture  the energy and speed of the music.  Clean and clear, not smeared.  Detailed, but not in an etching way.  The sound calls attention to itself ... you  notice the music when it is playing.

 A few weeks ago ... I was listening to Elton John's 'Live in Australia' on vinyl (new pressing).  I have listened to this album a lot for close to 30 years and this was the first time I was noticing the chestiness of his vocals and his pronunciation of certain words. The song that struck me in particular was 'Have Mercy on the Criminal.'  Very moving to feel that involved in the mix.

And maybe that is the primary emotion with the Zu Omens ... the music moves me.  I feel like I am a part of it.    

Because of the 10 inch woofer and high efficiency there is a lot of oomph to the sound.  These speakers make noise.  They also play very clearly, when played low.  A plus as I live in an apartment.    

I tend to like single driver speakers.  I have Omega CAM monitors in another system (Rega amp, Technics TT, Magnavox 630 CD player).

Hope the description helped.

Not sure what 'nano' means, but Zu does lots of innovation. The newer products are prolly quite a bit better than older models. 

Nano prolly is an unfortunate choice of marketing mumbo jumbo. But the
Dirty Weekend's I heard were wonderful paired with a Line Magnetic Audio LM-518ia.
I am interested in these speakers but a little skeptical of their claims on website

Then why not buy a pair and take advantage of their 60 day trial period to reconcile your interest with your skepticism?

The nano stuff is just the cone doping they use.  Lots of companies do it.  Trenner & Friedl use balsamic oil.  Zu uses some nano material.  

As a Zu owner, I'd say I think about nanotech when I listen maybe once a millenium.
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My experience mirrors yours.
To me, the most important characteristic of the Zu sound is its fullness. Not too bright, not too warm, not too detailed, but full and alive with little fatigue. My Def4s occupy the long wall of my living room that is 22x15x16, and the living room is one end of a 45x22x16 volume. They do not get lost. 
Any Zu owners listened to Wharfedale, KEF or Rega speakers to compare?
Zu : Overpriced speakers with too many unrealized promises. But decent speakers nevertheless.

Wharfedale: Overpriced junkyard speakers.

KEF: Decent speakers that somehow got elevated to an luxury brand in Hong Kong. Their showrooms there would make you laugh and roll on the floor. But deep down, respectful speakers that are as decent as Zu.

I cannot speak for Rega since I never care to own any.
I beg to differ.  I have been in the hobby since I was 13 years old, so we are talking 50 years now.  Granted I have never owned the true high end, but I haven't owned shabby equipment either.  

I acquired the ZU Dirty Weekenders a few months back.  The most exciting listen in easily the last 20 years in my systems.  I currently own Wharfedale (Denton and Diamond 10)) and have owned KEF (Q55) and Rega (Ara and RP1).  Not even close to the Zu, then again I have only owned pure bookshelf sized and large standpoint sized speakers of the other brands, as opposed to a floorstander.    

The other speakers that I heard that I was this excited about were from Focus Audio and that was at a trade show 15 years ago.

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Zu Def 4 does scale effortlessly. With the right equipment upstream I have the Goldilocks sound I've always wanted. Honestly, the sound is anything but bright but then an all tube system goes a ways toward giving them the right signal. 
Will say though that clean power helps a lot. 
Don’t know about there claims of nano-tech but I have heard Zu speakers and find them very good.  It helps that I sell a line of amps that work really well with them but I have heard a few models and like them a lot better than some of the similarly priced competitors.  
Nano is just a term describing scale. A nanometer is one billionth of a meter. Structures on that scale are described as nanoscale. Nano particle coatings shouldn’t bother you any more than using a microfiber cloth to clean your speakers. It’s a nice label to refer to the proprietary dope they use to stiffen paper cones and tailor driver performance. Sometimes it’s marketing, but sometimes it can also be the correct technical term.

I tend to be resistant to marketing. Salesman give me hives. I’ve only bought 3 pairs of speakers in the last 30+ years so my experience is limited. (Infinity bookshelf, Dynaudio floorstander, Zu Omen DW) I’ve only had the Zu Omen DW for less than a year. I think they’re great - articulate and dynamic. It’s an effort to shut down and go to bed every night. Right now my dilemma is whether or not to take advantage of the 100% trade-in and upgrade before the year is up. I had intended to try a bunch of different types of speakers, but I like these so much I feel I owe it to myself to see how much better they get further up the line. 60 day demo and $1000/pr make the DW a pretty good hook for Zu.
How would you compare the Zu sound with Spatial audio speakers? 
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@scott_w I think a fair amount of deliberation  and waffling is expected before a substantial purchase. Last thing I want is buyer’s remorse. I’m starting with some acoustic treatments first while I avoid commitment, and early next year I’ll most likely order a pair of Soul Supremes. The Omen Defs are still in the running, though, if I’m honest with my actual use profile, I think the Supremes are a better fit for me. 
Zu offers a generous 60 day home demo I believe. Generous as it's free shipping each way. Nice warranty too & customer service as good as can be. 

User Phil has amazing detailed Zu reviews btw.