If you can get past the glitches, you'll find a very fun game.
Mass Effect is a futuristic RPG/Third person shooter. It plays similarly to Gears of War with less emphasis on action and more emphasis on the RPG elements. The game can be "paused" at any time to use a great variety of powers from three different branches. Biotics are powers that allow the player to throw, lift and otherwise disrupt the enemies physics causing them to fly around and float helplessly in the air. Tech powers allow the player to disrupt shields, weapons, powers, and even hack the AI of robot enemies (one of my favorites). The final branch deals with weapon and shield buffing. I was sort of skeptic at first at the way a shooter would play with RPG elements but it all blends together nicely. The action doesn't feel broken up by having to pause the game, and the powers are all very fun to use.
The other really great aspect of Mass Effect is the ability to customize your character right down to what they say in conversation. You're given the opportunity to choose a male or female, various classes, and a full suite of facial features to customize the player with. In conversation you're given the ability to choose different dialogue options and depending on what you choose you'll gain Paragon or Renegade points. These points affect your reputation and skill in charming and intimidating various people in conversation. This can lead to some very interesting situations in the game, especially towards the end.
The problem however lies in some very annoying glitches. There are major problems with texture pop-in. This particular problem is fairly common, and really interferes with what is otherwise a beautiful game. Another major problem is the Mako, the land rover used by your squad . The aiming reticule is pretty wonky and doesn't seem to be an accurate way to aim sometimes. The thing also controls very strangely, and takes some getting used to. My final gripe with this game is the auto-save feature not saving often enough. I often found that the auto-save worked so far between segments that I couldn't rely on it. I suggest that you don't either, otherwise you may end up repeating a lot of things.
In the end the game is a solid purchase, but only if you're willing to forgive the developers. It may not be the developer's fault but rather the publisher's that there are these issues with the game. It seems like a delay on the release date could have solved these problems, but the holiday rush caused them to push it out the door. We may never know for sure, but I feel there's enough value here in the game-play and story to make up for the problems.