I recently upgraded Arturia V Collection 4 to 5. I've been using these VIs since version 1. Please be aware that this upgrade is more like a new release rather than an upgrade for one particular reason: new DLLs (plugins) are installed, and have little in common with the previous versions. In fact, I don't see any of the presets I've used and have set in SONAR projects.
 
Note about Arturia products, and many others I know: when installing, if I choose to install on a drive other than C, most of the product actually installs on C anyway. I have an SSD for my OS, and a much larger 7200RPM drive for content. However, most of these virtual instruments only install the exe's on the chosen (D) drive and install all other files (images, content, programs, samples, etc.) on C.
 
So, to save space on my SSD, I first installed the new version of V Collection (5), opened SPlat and used the plugin manager to edit my Favorites layout for synth plugins, and then proceeded to uninstall the previous versions of the Arturia instruments (using Control Panel). I then restarted SONAR and allowed the plugins to be scanned, removing the ones I uninstalled.
 
Then the fun began when I tried to open a project that used the previous, now uninstalled/removed, plugins. SONAR crashed. Not a blue screen, but a "hidden" dialog not found until I Alt-Tabbed that showed SONAR had stopped working and needed to close.
 
I reinstalled the previous versions that I knew I had used in that project, restarted SONAR, allowed plugins to be scanned, and then successfully opened the project containing the re-installed plugins.
 
 
Moral of the story - if you must make space, don't uninstall any Arturia 5 products until AFTER you replace the plugins in all projects wherein they are used.

i thought sonar showed a "missing plugin" dialog for missing plugins?
 
good info tho, thanks!

They are all totally rewritten versions, new GUi's, new Class ID's so SONAR can not do the replace thing or the VST 3 substitute thing.  One other real downer is that none of your custom patches or banks can be imported either.
 
Another moral is do not uninstall the V4 collection or old standalone versions as one day you might well want that patch you painstakingly created.

This is probably more appropriate in the software forum so I am going to move it.

Good to know. I was hoping version 4 would not be overwritten and that seems to be the case.

I am still undecided on the upgrade options.

How does the piano sound?

musichoo
How does the piano sound?

I have had a run through the presets in Analog Lab 2 and both the piano and the Rhodes sound good, but I have better. Same goes for the organs. Hence I am leaning towards just upgrading my v4 instruments.

One more thing, because the piano is modelled the sound can be manipulated and made to sound very different so that will appeal to a lot of people.

musichoo
How does the piano sound?

Not bad Choo I think you will find it OK there is more than one, a couple of different Grand's and a couple of uprights.

The B3 sounds quite nice as well.