Infantry do well under the same circumstances as they do in Boardgame/CBT. Put them in buildings, and they're terrors to kill.
In fact, if you do this, your opponent will probably catch on that the easiest way to deal with them is to just raze the building they're occupying. Make sure you watch the CFs on the buildings you're using as cover, and skedadle the turn before they run out :)
Also: anti-mech attacks are way more reliable than in Boardgame/CBT. Easier to pull off, and at Alpha Strike's degree of granularity more devastating. Put some infantry in fast APCs, and they become "KILL IT WITH FIRE" level of irritation to your opponent... giving your LRM carriers and such a possible reprieve from being fired upon.