the main advantage of the OS2 is it gives you a lot more virtual patch destinations - you can modulate the virtual patch amount of other slots as a destination, change envelope parameters, they also added filter 2 resonance as a destination, filter 1 EG amt, OSC control 2 (so you can make some great random changing or sweeping VPM sounds, s&h LFOs for wavesequencing, map keytrack to select different drum sounds (more on that later!), lots of new stuff!
apparently, you also need OS2 for the USB to work correctly in windows 7, or in 64bit, or something...
there is absolutely no reason not to upgrade to OS2, it is all improvements. If I were you it'd be the first thing to do when you get it.
and from what I can tell, you're a brilliant programmer. You'll be absolutely thrilled with the Radias!
Current Gear: Kronos 61, RADIAS-R, Volca Bass, ESX-1, microKorg, MS2000B, R3, Kaossilator Pro +, MiniKP, AX3000B, nanoKontrol, nanoPad MK II,
Other Mfgrs: Moog Sub37, Roland Boutique JX03, Novation MiniNova, Akai APC40, MOTU MIDI TimePiece 2, ART Pro VLA, Focusrite Saffire Pro 40.
Past Gear: Korg Karma, TR61, Poly800, EA-1, ER-1, ES-1, Kawai K1, Novation ReMote37SL, Boss GT-6B
Software: NI Komplete 10 Ultimate, Arturia V Collection, Ableton Live 9. Apple OSX El Capitan on 15" MacBook Pro
The KORG USB drivers are actually universal. its a good idea to make sure you have the latest ones from the website. Most of the stuff you find on the included disk will be outdated.
But for example I have the latest drivers installed and I'm using my Radias. Now I've got a nanoKontrol, I just plug that in and go to Start > Programs > ...Install KORG USB MIDI Device, and it will show the nanoKontrol in there to install
No need to download a separate driver. but you could take this opportunity to upgrade to the latest drivers anyway.
make sure you use the software editor that comes with the update though, and not the one on the disk/website.
the one that comes with the update supports all of the 2.0 features, I couldn't find it on the KORG site to download separately - you get it with the update. I found I was archiving some of my sounds using the v1 editor at one point - which is worrying because it does load and communicate with the Radias without any errors or anything. I think there is a risk that parameter settings that aren't in v1 will be lost if you do that. so make sure you are using the v2.0 editor.
there are instructions with the update on exactly what you have to do. I think it communicates to the unit over USB without actually using MIDI, so i'm not sure. You might have to install the drivers first. can't be any harm in doing so as most people who were using it before the update came out would have the drivers already installed too.
Current Gear: Kronos 61, RADIAS-R, Volca Bass, ESX-1, microKorg, MS2000B, R3, Kaossilator Pro +, MiniKP, AX3000B, nanoKontrol, nanoPad MK II,
Other Mfgrs: Moog Sub37, Roland Boutique JX03, Novation MiniNova, Akai APC40, MOTU MIDI TimePiece 2, ART Pro VLA, Focusrite Saffire Pro 40.
Past Gear: Korg Karma, TR61, Poly800, EA-1, ER-1, ES-1, Kawai K1, Novation ReMote37SL, Boss GT-6B
Software: NI Komplete 10 Ultimate, Arturia V Collection, Ableton Live 9. Apple OSX El Capitan on 15" MacBook Pro