As I usually don't mind if someone tells me they are using forgeworld stuff as it doesn't really matter. I just kinda feel like I dont get an advantage as the only models for Grey Knights they have are some two-bit Inquisitors... I suppose a thunderhawk would be cool but meh. Anyways the one time i can think of where I was like Oh My Gosh I dont believe I agreed to playing this game was when a Player back homes list was the following.
Landraider Achilles
-Techmarine, x5scouts
Landraider Spartan
-Techmarine, x5scouts
x10 Scout squad
Bray'arth Ashmantle
x3 Venerable Dreadnoughts
x3 Ironclads
Ofcourse this list isnt as good now but in 5th editions I felt alot of grief for my lascannon-less Greyknights My only hope was my NDK to maul'em in CC. We ended up with a draw for that game still