I have tried the midi files, Turbo Sounds, BK7M, and three different Ketron units. X4, Midjay Plus, and the Ketron SD 40. all of which I still own, except for the BK7 M
The Ketron choice in my opinion, is by far the best. My Midjay Plus required an add on and some fiddling around to allow the volume pedal to affect only the right hand sound, as it doesn’t have provision for a swell pedal. Once that was solved, it has been a very reliable unit, and I. Love it. I have since bought a Ketron SD40. It is somewhat smaller than the Midjay, but not as easy for me to program, so the Midjay Plus is staying with me until I have the SD 40 figured out. For ease of use, the old X-4 is the winner by a long shot, but is not as customizable as the Roland, the Midjay plus or the SD40. The Roland although easy to set up with my Fr3X isn’t nearly as good with the rhythms in my opinion. It has a Japanese approach to what they think you want, while my Ketron units are more along the style treatments I like. The Turbo Sounds is a program for the I Pad, that works well. It’s free to try, but isn’t my favourite. Now that I have thoroughly confused you, go buy a Ketron unit. They are bullet proof. The Audya is large in size compared to all the others I have tried or used…It would not be my first choice. Also a midi equipped accordion with real reeds over my Roland. I mostly use my midi equipped Victoria. Just something about those real reeds.