I know what you mean about 421s. I had one on a bass cab at a gig a while back, and it was totally useless.
So much spill, even though it was right in front of an SVT giving it's all. Made very useless by al the drums in it.
The bass tone I was getting from it wasn't very pleasant either!
I much prefer 441s. Tighter pattern and the tone benefits from this.
I've been using AT4050s on toms recently, and any time I've gone back to 421s I've beer very dissapointed.
I used to really like them, but have been put off every time I've used them recently.