Since you asked about other orchestral sampler options, I'll mention that I've had good success with NI Kontakt as a very capable and flexible instrument, although admittedly I haven't done a lot of sampled brass in my music. However, just listening to the Trombone patch in Kontakt (without any backing music) I think it sounds (much) better than the Miroslav Philharmonik you used in your song.
I've also heard good things about the East West Quantum Leap stuff, as John mentioned above, although I don't have personal experience with that.