For as great as the mana is in Standard, we haven't seen a ton of innovation from the decks discovered even before PT Battle for Zendikar. There have been a few less popular archetypes that have faded in and out of the limelight, but we're not seeing a great deal of new technology. That said, Painful Truths has come into its own in recent weeks. If you want an example of a deck that really takes advantage of the card, check out Danny Jessup's deck from the Standard Open in Las Vegas last weekend:

The Mardu wedge contains some very powerful cards, though has only really gotten a lot of exposure since the printing of battle lands and the surge of four color decks in Standard. This is the first time I've looked at a Mardu deck and thought that it might have what it takes to be highly competitive. Abbot of Keral Keep contributes significantly to the decks power, and Painful Truths really pulls everything together.

The problem with Mardu decks was always that you had no card selection. It was easy to run out of gas, and your good cards had to naturally come off the top. Jeskai Black solved this by adding some blue draw spells, and this deck does so without needing the splash. Painful Truths plays very well with the prowess theme of the deck and exceptionally so with Seeker of the Way. Another great aspect of this deck is that by sticking to three colors you're able to play a bunch of Shambling Vents.

I'm always skeptical of any white deck not featuring Gideon, Ally of Zendikar, but I'd definitely give a variant of this deck strong considering for a Standard tournament this weekend.