Man, why wasn't there a 'both' vote?
Admittedly, had you asked me this question about 6 months ago before I started seeing Top Gear and 5th Gear with any sort of volume, I probably would have said Tiff, outright. Nothing like a guy that you know is capable enough to thrash around just about any car successfully to inspire confidence in the opinions offered by the same person! He does the edgy thrill commentary to the hilt.
Jeremy took a while to grow on me, but I now think he's cool for his own reasons, just like everyone else. What Jeremy lacks in driver ability, he makes up for with humor and that rather scathingly sharp sarcastic tongue that knows no bounds of restraint (beyond what the BBC is willing to allow on TV, of course

)
Now throw Vicki into the mix, and it's apples, oranges and buns.
Mmmm. Buns....