I'm playing Sith - mostly because I feel like being able to say "you know what, you're useless, you deserve to die, eat lightning pew pew" but also because as "evil" as they are, the imperials do have some 'good' ideas.
War is good for people, its a sorry truth, but you don't have to do much thinking to realise that simple inexorable fact. The pursuit of the next big gun helps technology move on at a crazy pace. Medicine, particularly medicine related to genetics, was advanced a long way during the last world war. Even silly products, like superglue, were developed first, to stick soldiers back together.
Moving beyond that, the ideals the imperials have aren't that far off what most peoples inner monologue would tell them anyway. How many times have you walked down the street and seen a group of chavs, insolent kids or something and said to yourself "someone needs to sort them out"
The imperials are an example of what happens to a capitalist society with the shackles of morality removed. Disagree with paying taxes to fund the unemployed or unemployable? Why not round them up and "dispose of them", force them into indentured servitude or test stuff on them instead.. Don't like sub culture "x"? Outlaw it, kill them all or make them conform. etc etc.
At the ground roots, as any imperial player can tell you, most of the imperials (as represented by the in game NPC's) are pretty normal average Joe's, like the rest of us. They have normal needs and desires, and most seem to have a reasonable ethical stand point.
What's interesting is seeing how their reactions are coloured by the fact that they belong to a larger culture that permits or turns a blind eye to actions that even they might personnally consider a little extreme. They don't like to admit that they'd like some kind of lethal revenge on those evil smugglers from sector 7G, but hey if you want to go stab them all in the face while you retrieve those battle plans for me, my lord, I don't really mind...
The imperials are probably more like us than we ever care to admit, and anthropologically speaking, its fascinating seeing how we've been reflected in them.
Needless to say, I'm loving being an imperial for a change and kudos to Bioware for making them so believable.