Originally Posted by
Nonex
Veteran Explorer is good in metagames with very few basics overall. Think Canadian Threshold, RUG, etc. Basically matchups where only you get to search because they have nothing to find. If there are decks with at least 3-4 basics they can get as ahead as you, and it's a matter of seeing who can do more broken stuff. Blue control decks with basics (Miracles, or certain Landstill variants years ago) are problematic because they resolve their bombs and you don't. Against control decks in general you should board Veterans out; you don't need acceleration if the opposition is slow.
I don't have experience with Deathrite Shaman here, but it seems to act as the counterpart to Veteran: Veteran is broken in some matchups and mediocre in others, while Deathrite is never broken but always performs well. My advice: play Veteran if your metagame is aggro and/or aggro-control, and Deathrite if it's mostly control. And if you want to stick to Veteran and your metagame is full of blue control, always pack some Carpet of Flowers in your sideboard.