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.
• Generally used in hyper-mill setups with heavy recursion. If you are FULLY committed to heavy recursion, it's easier to use extra copies of Mganga than extra copies of Hokusai.

3/1s are usually unplayable (they're not efficient for getting agenda points and dilute your deck with agendas). The 3/1 agendas that get played either need either a great ability or an excellent interaction with a popular ID(s) to work. AR-Enhanced Security has both.

AR-Enhanced Security's ability is thoroughly excellent. It's a straight improvement on Controlling the Message's ID ability, which has been among the strongest corp IDs for years. CTM traces for a tag if an installed card is trashed. With ARES, a tag always hits (no trace) even if the trashed card isn't installed, making it better against Stargate and HQ/RND destruction. Along with CTM's ability, this is one of the most reliable effects to jack up the price of trashing assets so high that many decks can't keep up.

Runners right now have a slew of options for dealing with trash costs (e.g. Miss Bones) or bypassing trash costs altogether (e.g. Stargate and Imp). AR-Enhanced Security is a major reason that asset-centric decks are still an option out of NBN, though not as strong as in years past.

Your first ARES scored will probably inflict 3+ tags for a direct impact of 9+ credits. In addition, there are uncountable benefits like the cards NOT trashed and the runs not made because the runner is afraid. If your deck gets any value out of tags, there will be many situations where scoring this is a good use of your time, even though it does make deck composition clunkier compared to 3/2s and 5/3s. There will also be games where this lands the winning tag(s) and plays a crucial role winning on tags. As far as tag-dealing cards go, this is more reliable than most.

This ID takes a click-compression card which is probably too efficient (Seamless Launch) and makes it into a Frankenstein's monster which is used on every agenda score. Maybe 90% of cards that Precision Launch players bring back to their HQ are Seamless Launches. If they pass on Seamless Launch, it's because they already have one in their hand or their final agenda is Vitruvius.