Which do you like more?

[RxPhantom]

I know I just commented on your Mairsil thread, but I'm definitely going with Mairsil. I imagine him playing similarly to Merieke Ri Berit, who is helms one of my favorite decks. Tough call, actually, because I want to convert my old Rith, the Awakener deck to Samut.

Anyway...

VS.

[Dragoon]

Ahah, I was going to propose that exact same one since I just cut Despark from The Ur-Dragon. I'd go with Anguished Unmaking as I got burned by Despark not being able to deal with what I want too often.

To stay on the removal theme:

vs

[TheAmericanSpirit]

Endless Detour, by the thinnest of margins. It's only a hot fix, but it has a wider range and can be impromptu recursion in a pinch.

Mind Harness or Chamber of Manipulation?

[kirkusjones]

Endless Detour, by the thinnest of margins. It's only a hot fix, but it has a wider range and can be impromptu recursion in a pinch.

Mind Harness or Chamber of Manipulation?

Chamber, because it's a discard outlet with upside.

Pernicious Deed or Engineered Explosives?

[PrimevalCommander]

Pernicious Deed because it can pop for more than 4 or 5. Engineered Explosives is probably great as anti token tech if you play a LOT of token decks, or weenie decks. I tend to pop Deed for 4-6 cmc depending on the board state.

Ensnaring Bridge or Crawlspace

[void_nothing]

Crawlspace - both are absolutely classic control artifacts but in my particular decks I just have two open blockers. *shrug*

or

[BaronCappuccino]

Abrupt Decay - costs less, can't be countered, hits more types, and three or less is pretty relevant in today's tendency for EDH decks to feature beach bods rather than dad bods.

Already opted for the latter, myself, but opinion is interesting.
Phyrexian Arena ~or~ Black Market Connections

[void_nothing]

Hard to imagine displacing the mighty Arena, but I too really am liking Black Market Connections. It's so damnably versatile and you can pick all three if you're in a build that wants to kermit soup inside. In normal Constructed, losing 2 life versus 1 per turn is a big deal, but in a 40-life format it's a lot more tolerable.

or

[NotARooster]

I prefer Wood Elves, purely because it's mono green so I can run it in my gruul decks. Ghave, Guru of Spores or Marath, Will of the Wild ?

[void_nothing]

Marath. Ghave is the ultimate engine when it comes to these things but Marath has more utility and grows when you recast from the command zone.

or

[cheonice]

Grand Abolisher. Protects my plans and does not drain the fun out of any game like the Magistrate.

Heliod, Sun-Crowned or Archangel of Thune

[Sinis]

I love this game and I'm glad it's back!

Archangel of Thune. I like global buffs, and even though Heliod is a resilient and powerful option, Archangel feels more explosive, especially in a non-combo context. If I had to pick one, AoT, but if I were building a deck that had one, it would certainly have the other.

How about

OR

[void_nothing]

Volo Classic. Weirder, funkier, more combotastic. Plus, that flavor text!

or

[Myllior]

Faeburrow! Was so happy when it came out; a budget replacement for Bloom Tender was sorely needed at the time. BoP is an exorbitant mana dork.

or

[BaronCappuccino]

I'm going with Resculpt. Theoretically, blue isn't supposed to be able to permanently handle resolved permanents, and Resculpt takes care of two of the primary ones. Extra options are almost always worth extra mana in my book. 4/4 vs 3/3 seems like something I'd care about in modern, but not commander.

Battle of the development mistakes?
Beast Within --vs-- Chaos Warp

[Mookie]

Beast Within. Chaos Warp is technically harder to replace (red has almost no other answers to enchantments, while green technically has other answers to creatures / planeswalkers / lands), but if I'm looking to play a removal spell, I usually prefer the option with less variance, even if the expected value may be a little worse.

vs.

[void_nothing]

Ancient Brass Dragon. A relevantly bigger body and a beyond-absurd ceiling.

or

[cheonice]

Ramunap Excavator. She's a solid option, while you hardly can do anything fair and fun with Azusa.

or

[RxPhantom]

I'll still go with Excavator. No hoops to jump through to get the effect. They'd make a good team though!

VS.

[void_nothing]

I certainly like both, but Tornado Elemental wins out for me - the mass destruction potential and the supertrample are attractive.

Plus it's one of those weirdly abstract Elementals from the original Mirrodin block. Style points.

or

[TheAmericanSpirit]

The Angry Bean, of course. Rampaging Baloths is just... Bleh. Good in a landfall shell, but interminably boring.

Thresher Beast or Ravenous Baboons?

[Mookie]

Ravenous Baboons. I wouldn't play a 4/4 unblockable for 5, but land destruction always has a use (even if it is only nonbasics).

vs

[materpillar]

Open the Vaults
wwww is so much white for a card that's probably in esper for artifacts or bang for enchantments.

or

[void_nothing]

The two Big Vs are so different (in terms of their marquee abilities, obviously they both have the Praetor style of ability design and similar bodies deliberately) that it's hard to evaluate one against the other. Both have effects that take over the game, only one requires you to do particular interactions and the other is just - inevitable, locking opponents out of alternate turns and doubling your mana. I like Vorinclex, Monstrous Raider for the newness factor and the style points of using him in a Fynn, the Fangbearer jank deck.

or

Battle of the signpost uncommons

[TheAmericanSpirit]

Soulherder fo' sho. Between the raw power and Mckinnon art, it's an easy choice.

War Room or Bonders' Enclave?