Do they prefer E4B over the larger models or is it a matter of what fits their machine? I assume 4B isn't large enough to get interesting writing but I don't know anything about it.

Gemma4-31b seems to be very highly regarded for creative writing, especially its finetunes. As for comparison to E4B, I can't say.

Creative writing is not my focus, so this is only secondhand information. r/LocalLlama tends to focus more on the technical side; if you want more creative side check out r/SillyTavern as well (but type of info does bleed over between them).