[MPICH] But who is the best between the intercommunicator and intracommunicator?

[Eng. A.A. Isola]

I have a simple question for you...

But who is the best between the 
intercommunicator and intracommunicator?

Is better use an 
intercommunicator with Send/Recv or Bcast...
or is better use the 
MPI_Intercomm_merge and to use the Send/Recv or Bcast inside the new 
intracommunicator created?

I talk about the performance...is more 
faster the inter or the intracommunicator?
Do they have the same 
performance?The same speed?

Bye

Alfonso