BBM on Android needs to get with the program
All of the successful IM platforms on Android are useful because they go through GCM. Blackberry OTOH decided not to because they choose to be proprietary with their services alone. The result is that BBM messages do not always arrive in a timely manner.
Recently my tactical team tried it out as a way to coordinate between members who were off duty in the time period between being activated and arriving and those of us using android devices were not receiving messages immediately like iPhone and BB users due to blackberrys stubborn refusal to use GCM.
The reason we were test driving this in the first place is because one member suggested BBM uses better encryption but AFAIK it doesn't really, unless you ALSO subscribe to BES which is a paid service and still won't deliver messages on time anyway.