I also like Kroxigors but not because they are all that good, they are not terrible though, but they need to fight hordes, unlike many other "big guys" with 4+ wounds, they are very bad at fighting other big stuff, while things like troggoths, bullgors and such often have hard hitting high rend attacks, Kroxigors got 0 rend and only -1 rend on the moonhammer, which is terrible against low model count units. As such, my opponents like to charge them with their fast monsters

The moonhammer can do some serious damage though against big units, like grots, beast herds, skeletons etc.
The thunderquake can give you rerolls to wound and saves (or hit/charge rolls), and the Kroxigors can be part of this battalion. Once I liked to use razordons, as their ranged attack could make it easier to be within 8" of the engine of the gods (otherwise they lose the rerolls), but I found the best way to lock down the battalion units: the engine, bastilladons/stegadons can be swarms of chaff, and the Kroxigors make for a decent hard hitting frontline.
Beware if you play in a casual environment when you use the thunderquake and shadowstrike battalions, both can be very frustrating to an opponent and I have had friends grumble about it before, so maybe just be clear on what level of gaming you are doing and it should be fine.