If I had to start eliminating these choices off the island Survivor-style, I'd say Vona is obviously the first to go
My evaluation comes from my own biases, which boil down to: play the sort of cards and decks that lets everyone at the table have a chance to breathe, play Commander, and have at least a decent chance to do the thing that their deck wants to do
Vivi does everything a spellslinging deck loves
Creatures (24) 4 Ranger of Eos 3 Elite Vanguard 2 Goblin Bushwhacker 4 Goblin Guide 3 Kor Skyfisher 4 Plated Geopede 4 Steppe Lynx Planeswalkers (2) Lands (24) Spells (10) Goblin Guide wasted no time hitting the big time, appearing in everything from red aggro to Naya, including this Boros Landfall list Bram Snepvangers took all the way to the finals of the 2009 Magic World Championship
it currently sells for an average of $220
At the same time, red is a very haste enabling color, and most decks that can play this can also play better cards