Infusion Grid is a very efficient blocker, costing only 5(gold and blue) for a 4 Health blocker (able to absorb 3 attack). It would be strictly better than the base set Wall, if not for the fact that it doesn't have Prompt. As a result you have to buy it preventively one turn earlier, which is not always feasible (for instance against the burst from Gaussite Symbiote or Cluster Bolt).
Infusion Grid's extra 1 over a Wall means that it can also absorb one more point of damage each turn. This makes it very important to get at least one Infusion Grid provided the set contains no even bigger absorbers. In fact, in the early game, against an opponent with attack at1 or 2, buying an Infusion Grid instead of a Wall is usually better, since this allows you to get to 3 absorb right away at the cost of an Engineer (which is easy to replace if you even need the Energy). If you buy the Wall you will probably just need an Infusion Grid next turn anyway, and you'd overdefend.
In the mid-game, when you have spare , it is probably better to buy an Infusion Grid to cover next turn's defense than to buy a Steelsplitter. Buying an Infusion Grid will enable you to buy another Infusion Grid next turn instead of a Wall, thus getting you on a "train" of Grids. Being on an Infusion Grid train instead of defending purely with Walls allows you to block one more damage each turn without paying any additional resources, so it's like your opponent having one less constant attacker. Steelsplitter gives you one more constant attacker, which is a similar value, but it costs more than Infusion Grid. Compared to Wall, it gives 4/3 of HP for a 1 turn delay, which is similar to Drone or Auric Impulse, not very strong. It extends the Supply of defense available though, which is useful.
Infusion Grid's ability let you convert it into 4 Husks for the cost of 1 red. While that denies one Grid's absorb, it instantly gives you a lot of defensive granularity. If Infusion Grid is your biggest absorber you want to keep at least one intact to be your final blocker, but if you have excess converting some into Husks is generally a good choice.
Here is a good example of Infusion Grid's click ability being used to great effect: Z82l6-n4Kki. In this game, Tatsu Nullifiers were played on both sides, and so both players wanted to click their Infusion Grids to prevent the opposing Nullifiers from being able to chill anything big.
- January 8th, 2015