Hi Rubberdock and other posting forum members,
to answer your question I can give some additional information from my longer experience with 4 Styles providers (I'm a Genos keyboard player for 3 years, and other keyboards before) :
1) Styles-24:
Most of the styles are particularly good and they are as title-related styles very close to the original versions of the named artists.
As mentioned above, there are additional registration-banks for each of the styles. Only both together make it possible to play the song correctly.
However, it is necessary to play the whole song exactly (!!) as described in the instructions (= DOC- and TXT-file, describing how to play the individual registrations). A deviation from this playing procedure leads results in a performance which does not sound anymore correctly; a change of MAIN variations (differently as to the description) is not the right way.
The live played and recorded video on Youtube allows you to follow the process of playing the whole song.
There are no sheet music available. Therefore, if the keyboard player needs the notation, he has to buy it from a different seller. Often the notations are different than shown in the video of Styles-24. Midifiles are not offered for all styles. If available for the song, you can use a notation software (Sibelius, Musescore, etc.) to create the notes yourselve, however, part of the packages have special midifiles where notes can be shown on the display of the Genos.
When practicing the song in parts, you must always take the song passages from the beginning of a MAIN variation, otherwise there will be a mess.
2)Soundwonderland (SWL)
Here is the link:
https://soundwonderland.de/pages/de/shop/styles.phpFocus on styles are different genres of music that are offered. These are of very high quality and very good instrumentation, also with a lot of attention to details (!!). The styles are not title related, but are programmed to play a variety of titles (title lists as suggestions are often included). The application of the styles are shown in Youtube videos and described verbally, also in English. Sometimes there are only MP3 files with audio examples. Sometimes sheet music of own SWL compositions are provided.
3) D.O.O..
These styles (they are not packages like Styles-24)let you recognize the title-related song by the INTROs and ENDINGs, the MAINs (mostly 4, 6 or 8 bars long), can be repeated as you like, are loops where tracks are switched off or on in the MAINs. Text files are included. The quality is very different, the audio examples do not show the styles in detail, but are parts from a midifile. D.O.O. mainly sells Midifiles.
4) Keyboard Software
Here is the link:
https://www.keyboardsoftware.nl/Besides the title-related styles there are registration-banks and notes with stailed instructions how to operate the registrations with the styles. Those are packages similar to Styles-24. In addition, so-called LAP styles are offered, where special sounds (voices), audio files and pad files are used, but they have to be loaded into the EXPANSION drive via the YEM (Yamaha Expansion Manager).