On importing a MIDI file Metro *sometimes* puts program numbers into the tracks window. Such partial information is more misleading than useful and i propose to omit these program numbers altogether.
On exporting a MIDI file Metro generates several Meta-Events, eg. Sequence Number, Instrument, SMPTE Offset, Key Signature. I think these are generally rather useless and may even cause troubles in other sequencers. Thus i propose to export only (as usual): Tempo and Time Signature.