Scalenex's treatise on skrox covers just about every eventuality short of a new AB that provides some red-crested skink option with a mighty T3!! Just to highlight a few of the key points in the tactica, the skinks are extremely squishy and thus will give up combat resolution to just about anything. However, the unit causes fear, moves quickly, is immune to stomp and can dish out S6 hits. Another often forgotten quality is the ability of skrox to shoot - a key reason to give them a musician to permit a swift reform. A typical 3 krox block that reforms from 6 to 12 wide can dish out 18 poison shots and will retain 2 full ranks until the 19th skink dies. Given these qualities, skrox can be effectively used as follows:
1) Monster & chariot killers - between poison shooting, steadfast, S6 hits and immune to stomp, they can bring down almost any of the big nasties (hydra, chimera, HPA, gorebeast chariot, etc.) that will lay waste to TG or saurus.
2) Flankers - the speed & charge range makes them good flank protectors for the main saurus/TG blocks as well as excellent in providing support charges. They can be used to screen sallies from enemy troops , allowing the sallies to get into ideal firing positions.
3) Gunlines - The speed and relative hitting power against a gunline makes them perfect. By turn 3 they will be well into the opponent's rear area and can take out any "war machine", including the hellcannon.
4) Monstrous cav and S6 troops (irongutz, white lions, etc.) - Saurus/TG can't get through the 1+ save of much of the recent MC and get stomped while S6 kills them on 2's anyhow. Might as well be a skink dying and at least the krox have a good chance of killing some high value troops while the skinks take one for the team!