While the effect of making a player lose the game by paying one mana of every color is a nice shortcut, since it requires your opponent to have ten or less life, most of the time you're better off saving that mana for spells since they'll be defeated soon anyways
You can then tap it and remove it the counter on it to add the exact amount of mana you spent to attach the counter and card in the first place, and then that mana can only be used to cast the card attached to Ice Cauldron
Garruk is a little safer to flop onto the board, comes out sooner and easier and kills a little quicker than Bolas
Mother of Runes is horrifically polarizing
Shaun's last ability will exile all Synth tokens you control, not just Synth tokens created by its first ability
Crucible of Worlds One might argue that Crucible of Worlds and the more vulnerable Ramunap Excavator do much less than Conduit of Worlds, which is hard to argue with