I rather cast a vial or noble than waiting with a stifle in hand. Cracking a fetch CAN be devastating sure but let us be fair, in a meta full of artifact acceleration stifle can be very poor as well. I don't see stifle saving the day against a broken hand.
I agree with this statement. In fact, this was my original point. Stifle IS much more broken on the first fetchland which causes you to wait and give up precious time where you could be casting threats and/or disruption pieces. In an ideal situation, I feel that stifle is amazing. Also, I feel that when Brainstorm was legal as a 4x, stifle was MUCH more powerful. With the way things are in vintage at the moment, I feel that stifle is lacking.
As for Null Rod, almost every time I've resolved one, my opponent looked very ill (or very frustrated at the absolute least). If you play on winning with grizzly bears, Null Rod seems like a natural inclusion as it shuts down over 1/6th of most of the Vintage decks. In addition, it single-handedly shuts down the most played (and most powerful) 2 card combo currently in Vintage. Combine this with an assortment of other disruption spells/creatures and I believe it is a very powerful anti-strategy that hits the majority of current Vintage powerhouses.
@Guli:
I was really curious about your experiences with Canonist. I've tried her as sideboard against any type of storm/TPS. In almost every instance where she resolved, the TPS player would tutor up either Hurkyl's Recall or Rebuild and take out my Null Rod and Canonist at the same time. Do you really feel that it is up to par with your other disruption creatures?