To this point in my gaming life I have yet to be so enthralled with a game that I actually bother to try and do every single side mission (not even GTA). This is in a nut shell how great Mass Effect is, it does a great job of blending a great story (great voice overs, story, graphics, relevant side missions) and game play into one nearly perfect game. Despite the hiccups in the game play Mass Effect is probably the best action RPG I have played to date (better than any KOTOR title).
The new dialog system never gets old with options actually having an effect on the outcome of the game, so you will no longer be bound to meaningless choices that ultimately lead to one or if your lucky 2 outcomes. Also the new dialog wheel keeps players involved in the conversation. I can not tell you how nice it is to actually sit there and want to hang on every word that your character spits out.
The action in this game is surprisingly addictive and also fun. The cover system works well and the abilities that your character possesses are fun to use, incorporated well and actually relevant during the game. Your character will have access to different weapons and abilities based on what class you choose at the game and therefore will not have access to certain weapons and abilities based on what class you choose. I actually found this very appealing because you actually have to really think about what class you want to be because it may mean that you can not use an assault rifle or you may not be able to throw an enemy across the room.
Despite the fact that Mass Effect is a great game it does have its flaws. The all too familiar frame rate drops from the KOTOR series have made a special guest appearance in Mass Effect although I should point out that they are not nearly as bad as they are in KOTOR. Also the game has a reoccurring problem with pop in textures, so if you are a graphics snob you may want to stay clear. Your teammate AI is probably my biggest gripe with the game. It is in a word horrific; they seem to almost move around mindlessly and will spend most of the game lifeless and on their backs. This is a problem because the game is not scaled very well. The beginning of the game will be spent with frequent saving due to very challenging enemies but by the end of the game you are almost plowing through every enemy you see.
In the end Mass Effect is a great title and if you can get over the questionable AI you should find this to be a must play game.