Of the 101 cards available in the set, 24 are additionally available as Quarter Century Secret Rares, with one extra card only available in that rarity (Dragon of Pride and Soul)
Many of the cards not printed in this European release of this set were later printed in the European release of Magic Ruler (for those languages)
The Main Deck monsters, although weak on ATK, all have the ability of being able to give additional effects to "Armatos Legio" Link Monsters that point to them, which is described as "passing down their effects"
Sleeving every card takes up a lot of time, and I do not worry too much about minor wear on common cards
When goldfishing, it can typically threaten a turn 5 - 6 win (turn 4 wins are also not uncommon), which puts it as pretty fast for casual but keep in mind that interaction will slow this down (if the speed is a concern, see the Powering Down section below)
Here is the breakdown of the Top 30 Old Back cards currently dominating the heavy-hitter collector scene