[OMPI users] Best MPI implementation

Hi! I am going to start my approach to parallel programming (on C or C++) and I would like to know what should I learn/use, LAM MPI, OpenMPI, or any other MPI implementation. Can anyone advise me please? I believe OpenMPI would be best, but I can't find any tutorial on OpenMPI. Thank you very much

[OMPI users] Tutorial

Hi! Where can I find a introductory tutorial on open-mpi? Thank you ;)