From the upcoming May eZine (which isn't out yet), and covers VocALign integration:
SONAR Platinum includes VocalSync, which is an inexpensive solution for those with relatively simple vocal synchronization needs. However it cannot be added to SONAR Professional or Artist, and is not designed for use with musical instruments (only vocals). For those with demanding vocal synchronization applications, VocALign represents the culmination of over two decades of experience refining the algorithms that provide the multifaceted analysis needed for tight, accurate synchronization. The instrument synchronization thing is a major difference. If you want to consider the good > better > best paradigm, it would be VocalSync > VocALign Project > VocALign Pro. I've played with both the Project and Pro versions, and IMHO, Project will take care of pretty much everyone's needs unless they're doing really heavy-duty ADR replacement for film.