I upgraded without any trouble at all and found the new feature set useful. The plugins that were open in V2 opened in V3 . I didn't have to reload any licenses or update any plugins.
One thing I wasn't expecting is if you open a song that was recorded in V2 in V3, then you cannot save new changes to the V2 file, you must save it as V3. Since I like to preserve source material, this means I have to save a new version. Not a big deal by any means, just surprised me.
Can't help with the last two, but you won't suffer from the upgrade.