It's more flexible than Crisium Grid and protects all servers against a variety of threats. Problem: it's a low-impact card in many matchups, and there are so many 4/2s and 5/3s you could have played instead. Offshore Office -- by no means a top-tier agenda -- is 7 credits upfront. How long will it take your Transport Monopoly to produce 7 credits worth of value?

Popular "if successful" cards:

• It absolutely guts Apocalypse. They have to make 3 runs and then you prevent the third run from being declared successful. Then repeat this the following turn. Most Apocalypse decks do not have enough economy to run that much.
• Diversion of Funds. A Diversion of Funds that goes through is up to a 10-credit swing effect. If Transport Monopoly kills even one Diversion, absolutely worth it.
• Almost every runner (81% as of ban list 21.06) has Dirty Laundry. If you score Transport Monopoly, you could cut $10 from the runner. That's not terrible value for a 4/2. In some matchups, e.g. Shaper, this is probably the best you can hope for.
• It sets back Stargate 2 turns.
• It shuts down Counter Surveillance.
• It's a minor delay to Conduit. They could just run again.
• Hot Pursuit.

For reference, as of ban list 21.06, here are the most commonly used cards in standard which check if a run is successful:

• Dirty Laundry (used in 81% of runner decks)
• Stargate (29%)
• Apocalypse (27%)
• Diversion of Funds (20%)
• Conduit (16%)
• Hot Pursuit (10%)

(Minor examples include Embezzle, Wanton Destruction, Khusyuk, Steve Cambridge, CBI Raid, and Legwork).

This is the best end-the-run ice in the game*. It ALWAYS costs more to break than it does to rez. For almost every runner, this costs 4 to break with a breaker or 6 with no breaker, either of which are exceptionally high for a 3-cost ETR. In GameNET it reliably causes a 6-credit swing if they have a breaker, one of the most efficient ices in the game. Other ice that stand out on efficiency (e.g. Engram Flush, Slot Machine, Aiki, and Mausolus) usually lack end-the-run abilities or have gut-wrenching conditions (Data Ward is the most efficient ice in the game, but only if they're tagged).

Gold Farmer was removed from Standard because it is crazy-powerful in every matchup, on any server, against every possible configuration of breakers and breaker-alternatives. Among MANY other key applications, it is by far the most reliable setup piece for a turn 1 Daily Quest or Rashida install. (No breaker works well, paying through is a huge setback, and even Boomerang is no good). In GameNet, a single Gold Farmer takes Diversion of Funds from 2 clicks for a 9-credit swing to 2 clicks for a 3-credit swing. Ghastly.

Liabilities: none. It only ends the run, true, but at a cost of 3 it's best-in-class for reliably protecting assets and critical servers. This ice was concurrent with high-value, low-cost assets like Daily Quest and Wall To Wall and you absolutely could afford to spend 3 on a gearcheck to raise the cost of killing them.

Gold Farmer is so rawly powerful that it has no adequate counterplay, but more than that, it's so powerful it's hard to imagine what counterplay COULD be printed. If Gold Farmer's ability fires, it is virtually guaranteed to cause a 4-credit swing, which is an efficiency win for the corp even outside of GameNet. Even if the runner have a specialized breaker like Cleaver, which can break 2 subroutines for 1 credit, a 3-5 credit swing is still excellent for a 3-cost ice.

*Runners-up include Border Control and Surveyor. Border Control has a phenomenal ability, but I'd give the slight edge to Gold Farmer in value over time. Surveyor needs help and is kind of cumbersome in the 419 matchup where your early credits and installs are restricted, the runner has a trace, and Boomerang and/or Aumakua are usually available early. Gold Farmer is an A+ ice in every matchup, in every phase of the game.

Slot Machine is universally regarded as one of the best ices ever printed. It's extremely efficient and a nasty tempo hit. Against most common breakers, this usually causes a 4-6 credit swing, which is excellent for a 3 cost ice. It was removed from standard play because it was so strong against every breaker that it made good ice look unplayable. It ALWAYS makes sense to rez this. It will always cover its own cost, and it may even generate enough revenue to pay for its rez as well.

As a point of reference, Diversion of Funds is potentially a game-winning move (a 9 credit swing for 2 actions). A Slot Machine by itself will probably make this something like a 4-5 credit swing for 2 actions. That's a hell of an impact for a 3-cost ice.

The first subroutine is ALWAYS live. It doesn't care about the results of the slot machine. It doesn't even NEED slot machine results, it's live even if Hunting Grounds has killed the slot draw. The second subroutine is usually live (I'd estimate 65-75% of the time, higher in decks heavy on events).

Its third subroutine is rarely live, but there are some IDs where being able to place 3 advancement tokens on an installed card is valuable. (E.g. if you're playing advanceable ice, if you're playing shell games, if you're on Eternal Tennin, if you have a City Work Project installed, if you have an agenda out that you're confident that they can't get to, etc). Just having a third subroutine, even if it rarely matters, helps harden the ice against ice destruction cards like Hippo and cutlery.

One final note, I think it's cool having corp cards interact with runner deck composition like this.

Thoth is mainly useful for a tag on encounter, which I'd value at 3 credits of damage (+$2 earnings for Reality Plus, the ID where this is most widely used). It's usually cheaper for the runner to let the traces fire, so I'd value 1 net damage + 1 credit lost at another $3 of damage. An 8 credit swing for a 7 cost ice is excellent in Reality Plus. In Reality Plus, this is a significantly better ice than Funhouse. The extra $2 in rez cost is well-compensated by the runner taking a tag rather than having the choice to end the run.

If you're playing heavy on tags, you'll have a phase where you're trying to land tags and hopefully a "tag me" phase where the runner is willing to take a lot of tags and just go for it. This is the only tag ice very useful in both phases. At the point of the game where Funhouse is useless because the runner is already super-tagged, Thoth is potentially lethal and/or at least very costly.

Problem: the ice is unique, which makes it very inconsistent. Still, if tags are valuable enough to you that you're running 2+ Funhouses, including a Thoth is economically sound (assuming the Funhouses are).

Placement: I'd slightly favor RND over HQ. When the runner is super-tagged and you're trying to close out the game, I think the flailing runner's best chance for stealing a win is hammering a central, and Thoth will limit their options there. I don't think Thoth is as good on remotes. PS: Unlike Funhouse, Thoth is excellent against Turning Wheel farming and works much better as the outer-most ice.

• Problem: everything that Mganga does, there are better alternatives which last longer and create more value over time. Hokusai Grid costs you 0-1 more and is only trashed if the runner pays $4. It might even be cheaper if Mganga has an install cost. (God, I hope you're not installing Mganga alone). Hokusai Grid also doesn't get trashed on Stargate runs. Among ice, I'd recommend looking at Aiki, Anansi, Saisentan, and (Startup only) Engram Flush first.
• If your main goal is milling the runner, even Aimor is also more effective than Mganga.
• The only situation where I'd rather have Mganga than Aiki is in protecting Obokata. 1-2 reliable net damage may save Obokata. But it'd be a nightmare situation where I'd rather have Mganga than Hokusai. Consider all of the things that need to be true (Hokusai's reliable 1 net damage is no good, I NEED 2 net damage right now, and I have enough money to max out the psi game, and the runner does not have Engolo/AI to break Mganga). Stick with Hokusai, it's so much better in every other situation.