I think NEH FA/asset spam is a very difficult deck to play against, and Dumblefork is probably the best answer -- even if the matchup can still be very difficult against a good player.
Dumblefork's strength hits the deck in its one weak spot -- the NBN asset spam decks typically slot very little ice while your primary strategy is to destroy R&D ice and achieve a medium lock. Turntable is a lifesaver if the corp gets any scored astros by you. Whizzard's ability is obviously helpful, but you generally still have to be pretty strategic about what you trash because a) you obviously only get the recurring credits once per turn and b) the cards you absolutely need to trash or you'll definitely lose -- daily business show, team sponsorship, San San city grid -- still cost money to trash after you use the temp credits.
I saw 2 NEH FA decks at a SC last weekend and won both games, but they were both ridiculously close. In one case, I would have lost the next turn guaranteed if my medium dig didn't hit a the winning agenda, and that game was actually the less difficult of the two to navigate. I spent both games very poor almost the entire time because if I ever took my foot off the gas, more agendas were getting scored.