I have MIDI tracks of my songs that were made going back to 1989. Audio files don't satisfy me, as I like to grab MIDI data and rework it.
My setup in 89' was an SY77, E-MU Pro/Cussion, a TX816 FM rack (8 DX7s) and 2 TX16W samplers. I upgraded to the SY99, which was completely compatible, and I still have all the other gear The units still function and accessing old songs/sounds is a big reason I keep old gear.
After composing a lot of stuff on the Roland XP50, I bought the first Fantom, which is also compatible. I sold the Fantom to my stepdad, but he ended up not using it and giving it back to me, so I still have my Roland MIDI tracks.
During that process of possibly losing all my Roland songs, I had the Fantom play all my MIDI tracks to my OASYS sequencer. OASYS and Kronos have multiple track record, so I could just record a song in a single pass. I didn't want to make a GM MIDI file conversion. I did it that way, as I wanted to record/hear the tracks with the substitute sounds, in real time.
As for the sounds, I had to approximate the Roland sounds with Korg sounds. No problem with guitars, pianos, and the like, but with synth sounds, I just found something similar. Nice to have the category function on Korg synths, as I could just search for pads, basses, or whatever I needed.
I've had the OASYS, since 2005. I've done hundreds of songs on it, plus it holds all my Roland songs (about 60 more). You've probably seen
THIS video, where I play an exact copy of an OASYS project on the Kronos. Just as with the SY77 and SY99, and the XP50 and Fantom, I like to have compatible backups. Same goes with OASYS and Kronos.
For the long haul, I would definitely consider a Kronos 2. If not, I'm hoping Korg stays with this OASYS platform, as they have with the Kronos. That's 12 years, so far, of people creating and composing on the
same format. Indeed, longer than some Sony technologies.
Furthermore, when my SY99 dies, all those DX7/TX816 sounds that I converted for that are also available on the OASYS/Kronos, via MOD-7. There's a reason that I love these Korgs so much, and a lot has to do with the fact that they can make all the sounds that I was working with, 28 years ago! Yes, I sampled my E-MU drums and other sounds into the OASYS/Kronos, too.
As an example, here is a video of my gear in 1991. Check out the FM sound (TX816) at the 1:55 mark:
<iframe width="640" height="360" src="
https://www.youtube.com/embed/Wrv8_aQ0Azg" frameborder="0"></iframe>
In 2007, I posted this OASYS clip, using the MOD-7 version of the same FM sound, as above (about 11 seconds in):
<iframe width="640" height="360" src="
https://www.youtube.com/embed/OA_xrr7LALI" frameborder="0"></iframe>
In 2017, I still have all that stuff. I don't gig, so my gear stays in decent shape. I don't see my Kronos dying, soon. If so, Kronos 2 will cover it, as all my data is backed up to USB drives. I'm pretty sure you can keep your Kronos platform going for another 15+ years.