|The whole pack|
|The painted ones|
|Mauler pack as yet to be painted|
The Forgefiends I use all have 3 Ectoplasma Cannons which were pretty awesome at S8, small blast and AP2. Now they are pretty meh with S7, d3 shots and d3 damage, with no overcharge. It doesn't seem to fit that they have no overcharge risk vs reward option like most other plasma based weapons. I'd take the mortal wounds for the chance to buff output damage and strength. But GW clearly had other plans. For their price tag I think they are more there for rule of cool over actual awesomeness (I have had some stomping games but they are few and far between).
The Maulerfiends have so much damage potential but again suffer from the 4+ to hit big time. The Magma Cutters being effectively Melta Pistols is a nice touch if you can lock a big thing in combat. The Lasher Tendrils make mincemeat of most infantry too if you roll well for the number of attacks they get. I feel they could be a tad faster or have rules for scaling ruins and such as per their main purpose of siege crawling. Otherwise though I think I have had a bit more luck with these guys and they are a big threat when backing up Rhino based melee units.
Overall I like them still. I just hope the living rulebook nature of 40k now sees them buffed a little in the future or sees a points drop to make them a more viable option over a Helbrute or Heldrake.