So many pianos

The most obvious one is the Steinway model D. Apparently Steinway is in around 95% of the concert halls and classical recordings. IOW it absolutely dominates the classical world.
It also gets on a lot of the jazz recordings too. 
There's a reason why it has so many presets compared to all the others. It's the undisputed classical heavyweight king.
After that you have the B which gets in smaller conservatoires, halls, colleges etc. I'm sure that will also be on a lot of classical recordings.  Perhaps the B would get into more homes than a D would too?

The upright would be by suitable for all kinds of jazz recordings, pop recordings and classical recordings where you wish the scale to sound small and homely.

All of the fully acoustic pianos are suitable for all kinds of music. If you are making a mix I suggest listening for the one that sounds the best in the mix. This is trivial in Pianoteq - not so much in the real world!
Once you have captured the midi you can can click through them to your heart's delight.

Some people strongly prefer the early historic pianos for early piano classical works. Modern pianos having a clearer more crystalline pure tone. The purity of tone OTOH can also be seen as a lack of character. For this same reason some of the early pianos also suit some jazz and blues music for instance. The imperfections make things interesting.

There should be no hard and fast rules in Pianoteq though.

Have a listen through all the demos - take your time with all the music demonstrations on the website. You'll see how capable they all are in any genre.

If you want anything to cut through a Pop mix like a laser reduce the dynamics,  make it mono, make it bright with hard attack. There are already pop presets anyway.

Many thanks Key Fumbler and sskuk1 for your considered responses.

Yes, the question is subjective and I'm sure piano manufacturers wouldn't want to be button-holed into a particular 'style' or category of potential buyer.

But I am starting to get a flavour for some of the pianos that seem to give more when playing a particular genre... for instance, I find the Ant. Petrof really beautiful for Beethoven's bagatelles, the Grotrian just magical with Mozart and the Bluethner luscious with Debussy. However, my taste may change tomorrow if you know what I mean?

I'm still looking for a favourite for Chopin's waltzes … so far I'm favouring the C. Bechstein DC, but is this taken from old recordings and not the actual piano? I'm a bit confused with this one.

I think the option of tinkering around with morphs and layers for the time being is beyond me.

The Bechstein DG (Digital Grand) is a project of Bechstein Pianos (which you can find here) where they sampled one their pianos at Teldex Studios to create their digital instrument as a Kontakt Library. The Pianoteq model was created using these recordings as a reference. Usually Modaart records the pianos themselves but in this case they used someone else recording as a reference that's why the description specifies otherwise.

It was before lockdown I think, (Pianoteq began work on the C. Bechstein in 2018 irrc) but just that Bechstein required that Modartt use Bechstein's own sampling work as the basis, likely a kind of brand unification decision made by Bechstein, to tether all their licenced products of the era to their own exact preferred tones from their Teldex studio samples.

Often wonder how different Pianoteq's version might have been, if they themselves performed the sampling. I think they're top notch at that, rivalling sampling work done by any others. Each grand piano brand may have certain requirements which sometimes could shape the process, making things a little tricky at times I'm sure.

Hope you enjoy finding your preferred pianos DEZ. In my case, I remember happening upon Pianoteq when wanting a real upgrade from my various old software.

There was a piece I wanted to play using a better sound, and I tried Pianoteq out and just played the music using each demo piano.

At that time I was into the older era pianos but found the Bluthner was really charming for the particular piece - and I went for it because it kind of jumped out as an obvious win for my initial goal.

Then, they each began to intrigue me as I spent more time realising 'these people and pianos are more advanced than I thought possible' - each piano gives something complete and I find one may have an edge over another for 'vibe' or some other production oriented goal or other.. all really inspiring.

DEZ, also look at the two Kremsegg collections.  There are Erard and Pleyel options in those sets from Chopin's time.  While "authentic instruments" aren't always to everyone's tastes or project needs, I've always enjoyed the benefits (and challenges) to playing mid-nineteenth century works on those particular PTQ instruments.  Though, you get later era instruments from those same makers in the free instrument pack.  There's also another Bechstein in there as well.

That "Digital" label was bound to confuse casual viewers. Samples of the same acoustic C. Bechstein grand actually exist in a sample instrument which you can find easily online.
I don't suppose Modartt were brilliantly happy to have to use that same "Digital" moniker, especially when none of the other models are prefixed with digital.
It reminds me of the late 70s and early 80s when digital was the buzzword. It sounds curiously dated.

Then again their modelled version is far cheaper than the specified C Bechstein Digital Grand sample instrument equivalent, and considerably less hassle to download, and gobbles up no more space for existing Pianoteq owners!
That can be seen as a technical advance.

Edit to add link:
https://www.bechstein-digital.com/digital-grand/