As for the "quality" question, if you want to take price as a surrogate then the Century, along with the New Era and Prestige, was in the second tier of the London Made regular lines. Here's how the various regular lines were priced in 1974:
Virgin and Varichrome were priced at $30 each
Century, New Era, and Prestige were priced at $25 each
Mandarin was priced at $20 each
Prehistoric Perspex and Prehistoric Acrylic were priced at $23.50 each
Fantasy was priced at $21 each
Prehistoric was priced at $20 each
International and Tapestry were priced at $17.50 each
New Standard and Speciale Standard were priced at $16.50 each
Granitan and Ebony were priced at $15.00 each
Rockroot and Prehistoric Restlite were priced at $12.50 each
Penthouse was priced at $11.00 each