Almost everything is identical: it costs the same, does the same things, and is as completely busted as The Soul Stone is
It's also important to keep in mind that additional mana costs like command tax still grow Gyrus, so if you recast Gyrus a second time for BRG plus 2 mana for its command tax it'll enter with five +1/+1 counters so it does mitigate the downside of command tax
Japanese cards, promotional cards, tournament prize cards, and select holographics from early sets can also be extremely valuable depending on condition
Beyond the card drawing capabilities, its always useful to know whats coming up in your deck next
Designer Notes: Swarm the board with elves, then use your Commander to finish out the game
Replacing Duress in the main deck, Llanowar Elves enables explosive starts, letting you curve into Glissa, Sunslayer or Unholy Annex as early as turn two