From what I have seen,60s movies - I believe when it comes t consistency will be better than 80's era - simple nice stories,good melodies and good performances.
Social dramas,family dramas and Historic movies - all meatly done.
Its definetely more consistent than 80's movies - which had too much of masala movies.
But the 80's movies have too many peaks reached by balumahendra,mahendran,barathiraja,maniratnam - which will defintely win over those consistent movies from 60's.
And then there is Ilayaraja - who introduced BGM to Tamil cinema and introduced rollercoster orchestrations in his interludes and preludes - and we get to hear violins,guitars,flutes in that ride.