I recently purchased Mass Effect 1 and Mass Effect 2 in preparation for the release of Mass Effect 3. 
I have to say, I can easily see why people respect these games. The vast expansions to the universe is breath-taking, and the amount of content on the disc is astonishing. 
The character building and stories in both games is amazing, although there is a large different between Mass Effect 1 and Mass Effect 2. The changes have improved game-play alot. Although, they may have swung more towards a shooter then a RPG in the second, but that's just my personal opinion. I truly respect the Mass Effect series, and am very excited about the up and coming Mass Effect 3, and hoping it has great balance between the shooter game-play, and RPG mechanics.