Short version of this post: Play the game for the story and the difficult choices, don't get excessively excited about the gameplay.
I will try to avoid spoilers as much as possible. What I can say, however, is that, as far as computer/console "RPGs" go, Dragon Age is in the top tier. It involves some of the best "roleplaying" that could possibly be obtained from an unthinking unfeeling computer. There are few choices in the game that can be clearly defined in terms of "good versus evil" - you often have to consider the struggles of getting results now vs. doing things the "right" way, the idea of allying with evil people to fight an even greater evil, the tradeoffs between justice and mercy, whether or not the ends justify the means, and many other subjects which are rarely touched upon in the media of games. The world in which the game takes place is detailed in all of the right ways, so that you can more-easily imagine yourself living within it. Heroes are made by their deeds, and the manner in which the player-character gains prominence is much more believable.
Best of all about Dragon Age is its Non-Player Characters. As an ex-fan of computer & console "RPGs," I often found the characters in the genre to be either childish, stupid, flat or all of the above. Dragon Age does not fall to this folly - the NPCs are about as well-developed as is possible within the strict confines of a computer game. Its characters are up there with those of games like Tactics Ogre: Let Us Cling Together, Final Fantasy IV and the Baldur's Gate series. Even those NPCs who seem to be too-stereotypically "evil" still have their reasons and can be reasoned and bargained with, given the right choices and circumstances.
The gameplay is not so great, unfortunately. It is rather standard, and more than a little influenced by MMORPGs. This means that characters are expected to fit neatly into roles such as "tank," "DPS," "crowd control," etc., and if you do not manage these roles well, you will have an extremely difficult time completing the game. Combat strategy usually consists of planning the correct way to use special abilities and spells. Even worse, these abilities and spells have cooldown timers and are very inflexible, with their effects being altered only by certain stats. Ultimately, by setting the gameplay difficulty to Easy, you ought to be able to work through the game quickly enough to gloss over the combat system. If you are one of those pen & paper gamers who actually likes MMORPGs and D&D 4e, then you will at least get a bit of preparation for Green Ronin's version of the game.