Originally Posted by
RhoxWarMonk
As someone who has experience with both the white splash and the straight U/G deck, I can say they both have their advantages.
I was on the white splash for a long time but fairly recently I reverted back, now that lands isn't such a popular deck. Let's see what we really get with the white splash -- common SB options with white splash include:
RiP x2
StP x2-3
Absolute Law x1-2
Savannah x1
This is, on average, about 6-7 sideboard slots dedicated to the white splash, which feels like quite a lot. What you get is some very good game against decks like Lands, Dredge and Reanimator but none of these decks are very popular right now, at least in my area. The other thing that was already mentioned, is the land base is not as consistent playing the Savannah as it normally would be. Despite it being only one land, when you see your hand with some blue cards, a Savannah and a basic forest/Wasteland/Inkmoth, you'll be forced to mull regardless of how powerful your hand is in most cases. This edge case comes up much more often than I expected it to.
Now I've been running a copy of Grafdiggers Cage against Reanimator/Elves and a copy (or two, depending) of Surgical Extraction. This opens up an extra 4-5 sideboard slots I can use for other, better utility cards.
Which one is better? There's not really an answer for that question, like anything, it really depends on what you're expecting to play against. I found I was dedicating way too many SB slots for decks that I wasn't playing very often but as with any meta, your millage may vary.