Thks Jeff

You can either download the installer, run it on the computer you wish to install S1 on and then use S1 to download all the various packages (.soundset files) OR download the installer and all soundset files (my presonus->my products->S1 v3->Get All Content), run the installer and then afterwards double-click each soundset file to install them.
 
I keep the windows installer and all soundset files on a NAS box.

ston
 
I keep the windows installer and all soundset files on a NAS box.

This.
 
Not only for S1V3 but for EVERYTHING that I pay for and download.

I quite like Studio One 3. At one time I thought I might change over.

Sonar's Mix Recall keeps me here, though The Arranger track and Scratch Pads came close to making me jump ship. BUT I can replicate arranger tracks and scratch pads in Sonar but there is no Mix Recall anywhere else.

Another thing going for S1 is that there is a real ecosystem of hardware that is becoming more closely linked all the time. Mixers, speakers, software all coming together.

mudgel
Another thing going for S1 is that there is a real ecosystem of hardware that is becoming more closely linked all the time. Mixers, speakers, software all coming together.

What advantages does that have? Does S1 have special features that "speak" to them?
I ask because I have an Audiobox 22 which works identically in Sonar and S1 afaik.

There are some low latency features with some interfaces and Studio One. 
 
But it is more common for things like the CS18Ai mixer that are interesting.  While they can function as a complete control centre for the RM live hardware stuff, that mixer can also leave the Live Sound mode and instantly switch over to a very powerful Studio One control surface.  Even while it is doing a live mix controlling the RM hardware.
 
That is the sort of thing that would only work with Studio One in terms of control surfaces etc...Studio One may impart more remote control over the new 192 interface as well.