I have found the following labels to have provided excellent sounding recordings with a high degree of consistency, although unfortunately a number of them no longer exist:
Accent
Astree
Audiofon
Chesky
Dorian
Harmonia Mundi France
Harmonia Mundi USA
Hyperion
Lyrinx
M&K Realtime
Mercury Living Presence re-issues
North Star
Pierre Verany
Proprius
Reference Recordings
Sheffield Labs
Syrinx
Telarc (many are excellent; some will be disappointing)
Valois
Wilson Audio
Regards,
-- Al
Accent
Astree
Audiofon
Chesky
Dorian
Harmonia Mundi France
Harmonia Mundi USA
Hyperion
Lyrinx
M&K Realtime
Mercury Living Presence re-issues
North Star
Pierre Verany
Proprius
Reference Recordings
Sheffield Labs
Syrinx
Telarc (many are excellent; some will be disappointing)
Valois
Wilson Audio
Regards,
-- Al