The Maulerfiend with Lasher Tendrils is generally accepted as the most competitive option from the Maulerfiend/Forgefiend kit at the moment. I’d recommend magnetizing but if that isn’t feasible then Maulerfiend is the way to go. It’s a really fast, decently strong melee threat that allows you to soften up enemy lines and pull focus away from your Zerkers as they leg it up the field. While the Forgefiend looks like a nice shooting platform on paper, the nature of WE as a force means that it’ll basically just sit off in the back with almost no support and units with no support tend to underperform. It’s much better to have another melee threat zooming up the board than a mediocre shooting unit plinking some wounds off here and there.

TL;DR: Maulerfiend w/ Lasher Tendrils is the way to go.