Pros

• A very hard counter to viruses
• The most versatile of ambushes, it triggers from everywhere
  • can be triggered from runner access in R&D or HQ
  • triggers from Archives, so virus decks can never run Archives once one of these is in there
  • As an upgrade, can be installed in the root of HQ or R&D after being drawn to ensure a run on that server will trigger it
  • can be installed in naked remotes to have a curious runner trigger it
  • can be installed in a defended remote to masquerade as a non-advanced agenda
  • can sit alongside other high-trash-cost upgrades/assets to potentially defend them from Imp (depends on order runner chooses to access)
  • can co-exist in a server with an Agenda to force the runner to suffer the loss of virus counters as a cost for stealing the agenda
• For 3, the Corp can trigger this (by rezzing then trashing) during the runners turn, during a run, right on encounter with an ice

Cons

• A silver bullet card, it is almost completely a dead draw against runners that have no viruses (some small bluffing value remains as an upgrade)

Notable Interactions

• The best counter to Clot for Fast Advance decks. Use your SCG or Biotic Labor, fully advance your agenda, then in the final action window of your turn, do the following 3 without ceding priority: rez this card, use its trash ability, score the agenda. The runner cannot interrupt this to use a Clone Chip to the Clot back.
• Strong counter to decks that rely on Datasucker with fixed breakers - Mimic, Yog.0, Atman - or with Parasite to destroy an ice on encounter.
  
  • Note that some of these combinations are common in Anarch, Shaper and Criminal decks scenario is common.
  • To use it against these, install it in server protected by ice they will need to use Datasucker to reduce strength of - eg Archer - then after they commit to encountering the ice (by opting not to jack out during the approach), at paid ability window on run step 2.3, rez and trash this. Now they will faceplant into the ice, as at step 3.1 of the run they will have no datasucker tokens left to reduce the strength of ice into range of their fixed breakers or to strength 0 for Parasite.
• Works in a similar fashion against Crypsis or Darwin. (They will be able to use Crypsis against the current ice even without virus tokens, but then will have to trash it.)
• Moderately good against Medium. Weak as an access from in R&D, as the current access will continue to the full number of cards even if this is accessed and clears the Medium of virus counters. However, can be strong as an installed Ambush, as you can trigger it after they commit to accessing, but before access begins and they will then access 1 card only.

Final Thoughts

• Definitely a meta-call card. If your meta is heavy on viruses, especially Datasucker, or your deck is weak to them, then consider including a few of these in your deck. It will do solid work for you against virus decks, shutting down the runner's plans, wrecking their rig with surprise ice subroutines firing, or opening scoring windows by making ice impassable for a turn or more.