Magic: The Gathering Online sounds like the full package: pay for a virtual version of just about any Magic card every printed and use it in a deck online against tons of other opponents doing the same. If nothing else, it's good practice for your next Friday Night Magic tournament.
The main problem, though, has been the game's user interface, which looks and feels more or less like early 90s software and is practically unusable by today's standards. Fortunately, the team has been working on a new UI, which you can see above and below. It's not exactly Duels of the Planeswalkers, but it's vastly more usable looking than the current one. Note this is not necessarily the final version of the UI.
The new client is now in closed beta, but will be entering open beta July 16 for nine days. A "wide" open beta will come later this year and will last for an "extended period of time". Some time after that the new client will be official, live for everyone, and mandatory.
Other improvements beyond the UI are being made, and more will be made over time, but this is the key one, and something the team says is necessary before they can take on certain other aspects. For the full rundown of all the new features, hit the source.