If your local Simic player ever complains about not being able to deal with a big boardstate, show them this card
White can do taxing, which means it can have the text "counter target spell unless the opponent [pays a cost]." Now, cost has to be something players can pay the majority of the time because otherwise it just becomes too similar to counter target spell. White taxing makes the opponent choose whether to pay the tax, but that means the tax has to be a real option for the player
Im not trying to blow any minds by saying you need to know the Magic rules to understand what cards do
That's a lot of value and power per card, which is certain to pull you ahead over time
Boromir is also cheap enough that if you need to sac it, you can easily recast it soon
If you read my The Brothers War Set Review, you may remember how highly I think of this card, as it is largely a better Outpost Siege: even if we whiff, we at least get a Powerstone, which can help pay for Sethrons activated ability, and it doubles the number of cards we see each of out turns