With the latest set of Magic: The Gathering (MTG) - Innistrad, one of the new mechanics is "Transform", and this affects Double-Faced cards. Never before has MTG had cards where a playable face has been printed on both sides of the card. The cards that have the "transform" mechanic on it can be found on Wizard's Gatherer website.
I have been using cards with the new mechanic for around a month, and I am pleased to report that they are working well from my observations. I initially thought that would be difficult to use, with either having to flip them in sleeves, or requiring use of the Innistrad double-face checklist card, but it has proven quite easy - as long as I am given the time to set up the method you want.
Although I do use opaque card sleeves, and therefore I am permitted to use the double face cards in the sleeves, I still prefer to put the checklist cards in the opaque sleeves, and the actual card in a clear double sided sleeve. I do not know if that fits with the general consensus on how the majority of people use their cards, but I believe it cuts down on wear and tear of the actual card itself.
The cards themselves are good. If you can transform the card, so the the back of the card is showing, then the majority of them will provide a great benefit. I have charged to victory around 6 times (out of around 10 games) after getting out Ludevic's Test Subject, and within a few turns being able to transform it to victory. In one of those games, I was able to "pump" it up with Spectral Flight resulting in a 15/15 flying lizard with trample. The other good Double-Faced card is the Reckless Waif - a one-cost red human werewolf. Getting him out in your opening play (especially if you go first), will usually result in you transforming it by your second turn as your opponent will usually play a land, but not much else. This is not always the case, but the times I have been able get him out will usually result in me landing a 3 point hit in my second turn. With some good deck planning, I am usually able to get out some more creatures to come in and either defend, or add to the attack.
All I need to do is to figure out how to transform my cards to the more powerful side, and keep them that way. I have been caught out before by accidentally transforming my werewolves back into their human form by casting two or more spells. Anyone have any strategic tips?