Each booster contains twelve randomized cards, 6 common cards, 3 uncommon cards, 2 rare, super rare, or legendary cards, 1 foil card (random rarity level)
There are only a handful of different Enchanted cards available in each set, and they are mechanically identical to the regular versions of the card
As another example, if my opening hand has a one-drop, a two-drop, a three-drop and four different four-drops, then I will usually bottom the worst three four-drops in the hope of drawing into a powerful five or six-drop, while keeping the cards that will ensure a perfect 1-2-3-4 curve-out
Also shown off were two upcoming legendary creatures, which can be used to head up players Commander decks in the popular format
There are a number of resources out there that allow you to plug in your decklist and get a breakdown of what percentage of your cards need specific colors of mana, what the average converted mana cost of your cards is, and other helpful information (Im partial to Tapped Out personally)