Vanguards are the best class in mass effect, both 1 and 2.
Let's ignore the fact that in any king or emperor's army the elite soldiers guarding the dignity were called the vanguard, vanguards offer the perfect blend of stealth and combat. For all the people who like playing as a tank sort of character vanguards are basically perfect for this. Not only do you get most of the super awesome weapons soldiers get but you also get the super BA powers that biotics get. How is that not a winning combination? The best strategy is, when encountering a group of soldiers to use a couple biotic powers to keep them off-guard, then you pull out all of your soldier powers and beat them.