Excalibur is the Grail unlike the other Grail. Sharing nothing in common with the other ICE of it's type (Galahad, Lancelot, Merlin), Excalibur can only be revealed, unable to reveal its buddies itself. And it can often be overlooked, allowing many runners to save a credit or Cerberus "Lady" H1 counter when used with the other Grail ICE. No, Excalibur is a beast of its own. I see it as:

Neutral Trap ICE with a nice effect

Trap, because Excalibur notably has no ICE type. It cannot be broken except by AI breakers.

Excalibur, instead, hangs out with the Upgrades. For a measly 2 credits, Ash 2X3ZB9CY, Red Herrings, and Caprice Nisei, along with other strong Upgrades that typically require a second clean run, become maximally efficient. Excalibur + Red Herrings in a server means that the Runner will pay those 5 credits.

Ultimately, try to separate this card from the Grail subtype. In fact, I would instantly cut it from decks running the actual Grail ICE. I firmly believe this card is strongest when slotted into Glacier-style decks that intend to score in a remote, who naturally run powerful Upgrades to protect them.

I have found this ice to be particularly great in RP as the runner is forced to run a central server. Plop it down in front of HQ and/or R&D while having your score server ready with an agenda. Rez it when they run either central server and BAM, an open scoring window. Make sure that that you have Swordsman out in case they are running AI breakers, they only thing that can stop this ice in a hurry.

Excalibur is a welcome addition in the neutral ice. Having a neutral ice with the mythic subtype help.

It is a well balanced card, but less powerful than it seems. Let's first start with its qualities.

1. It is mythic, meaning there is only 5 things you can do about it : use a AI breaker (Aumakua), use Engolo or any other painting ability (Pelangi, Rielle "Kit" Peddler: Transhuman), or bypass it, use any of the single use breaker (Kongamato], Boomerang, Gbahali). This seems like a lot, and it is. Mythic subtype is not the greatest thing, but it is better than any other subtype.

2. It is cheap for its effect. 3 creds to rez with a strenght of 2. Not bad at all.

3. It combine well with card that give the corp end the run (ETR), like Bio Vault or Border Control.

4. It is a defense against Stargate and Medium by not allowing multiple runs. Shaper usually use Engolo, so it will not deter a Shaper using Indexing.

The bad part is pretty simple : It does not end the run, and it does nothing against runner who normally do only one run per turn, like most Anarchs and stealth Shapers. Also, it is unique, meaning you cannot put it on two centrals and a remote. Having 2x of it, unless you strategy rely on it, is useless.

Slightly above average card, same goes for the art and quote. Good to see it back in the meta.