Excellent RPG, marred only by technical issues
Mass Effect has nearly everything you would want in a RPG; a great story, realistic characters, relatively deep customization, and a universe worth spending time in. Bioware nearly stuck everything. Where Mass Effect slips up is on the technical side of things. The frame rate and load times detract from the experience. Remove the technical miscues and you would surely have a five star role-playing game.
After just playing through the Bringing Down the Sky DLC, you wish Bioware would have cut out the number of boring planets and spent more time on creating immersive side missions. The main storyline missions more than make up for this though.
Overall, I highly recommend Mass Effect to anyone with a slight interest in Sci-Fi or RPGS.