No,
BPS is a new platform.

It's more than BIS and less than BES.

BPS it's limited to 30 max users

BPS can install in the same saver that Exchange or Domino.
Don't have management roles and groups.

NO support IM IBM Lotus Sametime or Microsoft Office Live Communications Server
YES support Gtalk and Yahoo

NO support applications requiring BlackBerry MDS Runtime.
YES support Browser applications and Java applications.

If your requerminet grow then you can migrate to BES server.