They're as far as the eye can see.
Walk or drive along the major thoroughfares and the posters are plastered to any available public space. I thought that political advertising was bad in the United States, but in Argentina it is literally an urban street art form. Plaster a poster with the same face 300 times on a public space, expose it to weather, pollution and graffiti and you have quite a work of art.
As it specifically relates to the election, there is an interesting situation that is occurring in Argentina that echoes U.S. politics - the sitting first lady of Argentina is running to replace her husband as president. Apparently she is very intelligent, a current senator in the Argentinean Congress and a heavy favorite to succeed her husband a few weeks from now in the election. The Argentineans call her "Queen Cristina" and she certainly has shrewd political instincts. If she wins she will follow a trend that includes female presidents in the Philippines, Indonesia, New Zealand, Germany, Liberia and Chile.