Gloomspite Gitz are cunning, underhanded but perhaps for conversions purposes more important FUN as an army, from bounding squigs that are fundamentally space hoppers with teeth, to fanatics building so much momentum with their balls and chains that they are thrown down the battlefield themselves. It is an armywhere you can embrace the madness and joy of the fungus addled grots and their utterly insane ways to create something that embraced both sides of the funny/cruel sides of their factional personality.
With Troggoths as a subfaction within the tome you have the option of going for big lumbering brutes instead, perhaps not the most gifted with intellect they possess a slow resolve and brute force that constrasts with the grots beautifully and with their larger size provide a much bigger canvas to convert upon.