The M30.1 probably sounds heavenly because it is driven by a tube amp (Luxman LX-380). I have only listened to the M30.1 at the end of a solid-state amp and although the speakers still sound great, it appears to me that they only sound good with specific music genres. In my mind the M30.1 is not as versatile as the Super HL5 Plus which is more of a balanced all-rounder to me. The M30.1 is particularly great for vocals, acoustic music and small ensemble jazz but falls short with larger ensemble music and pop/rock.
If the M30.1 sounds great with the Luxman, do stick with that combination. Tubes can sometimes give a little glow and illumination to the sound. The setup that I listened to sounded a little dull, though the same cannot be said with the Super HL5 Plus which sounded more open and vibrant than the M30.1 with the same (solid-state) amp.