With the release of KAITO V3, Crypton has set up a special site for Piapro Studio, the bundled VOCALOID editing software package. Currently there is not much there except for a link to the original demonstration video and a list of frequently asked questions. The FAQ page does include some useful information.
For example, it appears that Piapro Studio may glitch audio-wise when playing a sound for the first time, although repeated playback uses cached information so it does not continue to glitch; they hope to ameliorate this with a subsequent patch. Furthermore, it appears that Tiny VOCALOID Editor may need to be started once after installation in order to activate the KAITO sound bank so that Piapro Studio can see it. Currently, Piapro Studio seems to only support a 44.1kHz sampling rate, although future updates are expected to add others. Since VOCALOID synthesis is very processor-intensive, they recommend setting a long buffer size.
Crypton has also released patches to Piapro Studio already, which can be downloaded from their support page; people who cannot get their auto-update to work are recommended to download a patch from that page. The updates also add support for VSQX export and VSQ import, and they fix several bugs as well. Currently, the software cannot import MIDI files, although they’re investigating the possibility of adding that in a future update.
Lastly, Piapro Studio is a VSTi plugin, and thus it requires to be run from within a VST host, such as the provided Studio One Piapro Edition. It is also currently only a 32-bit plugin, which means the host application has to be 32-bit as well, although Windows itself can be 64-bit. They are looking into adding 64-bit support at a later time through updates. Furthermore, as many people already know, the VOCALOID engine does not run on Mac, and thus Piapro Studio will not run on Mac either, as they use Yamaha’s API. Lastly, the FAQ also seems to imply that Piapro Studio was written on top of OpenGL and requires version 3.0 or later for proper display.