I've been playing them for a few months now at 555 and, honestly, they aren't needed at this size. I thought with the extra enemy tricolor additions we'd need the extra fixing, but we don't. They'll likely get removed soon and just take us back down to an even 550.
Personally, I think that they are kind of must have in a 720 and more cube if you don't want to cut the 3-4 colors decks. They are really useful if you want to maintain multi-color crafting in your cube. But if you're okay with 2-colors only decks, I think you could be just fine without it between 630-810. Above that, they are staples.
I run the 5 Vivid lands, 6 lands in each guild and the obvious multicolor lands in my 720 cube. I am considering to cut the Vivids and add another land in each guild section, but I am happy with it so far.
If your cube is anything but powered or bleeding edge of unpowered and like 465 or less, I think you run the vivid lands. Really tight lists don't like the tempo lost, but in bigger lists and slightly slower lists I love the vivid lands. They always feel great to play and fixing you twice is almost always all you ever need.
Do you play the whole cycle, or leave like, say, the red one out?
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I like the vivids a lot and run all 5 at 450. They are great in 3 color builds and help make filter lands better too.
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