Ok, well, I guess I should be explaining myself better. RiR isn't obsolete, but I'd say it's no longer the "definitive" Maiden DVD; I'd hand that to En Vivo now.
From a technical level, I think it's hard to deny Vivo's got better picture, and sound. From a setlist and performance perspective, it's a bit more subjective.
The DVDs feature 9 or 10 songs in common which are Maiden classics that get played at almost every show, and then some additional album songs and throwbacks. RiR has lots of Brave New World, and a few nods to the Blaze Bayley era, plus "Run to the Hills" and "Sanctuary". En Vivo has lots of TFF, plus "Dance of Death" and "Running Free". In both cases, I think the concerts could have represented their albums with better material (BNW and Navigator insteady of Silent Planet and Thin Line? Talisman and Coming Home instead of Avalon and TMwwbK?). But, in the end, it really evens out since I like both BNW and TFF equally. What becomes the deciding factor for me is basically the huge technical advantage that Vivo has.
Also, the Vivo stage design is glorious. I love the whole Space theme and the starry background, and probably like it so much because of my great memories from the TFF show I went to. IIRC, Rio is pretty bland by Maiden standards.