Wow. Love the detail on the faces! I can appreciate both styles of drawing, though. Simplified styles like you normally do, as well as these ones that err more on the side of realism.
Not just the faces though, the detail on the bodies is great. If I can offer some C&C, I'd say the angle of Ribbons' hands resting on her bust just seems kind of... off. The left hand seems closer to the correct angle, but they just feel like they're resting in a position as though her bust sticks out more than it looks in this illustration.
Keep it up.
I just had an idea for a series of images if you need any inspiration - What about images of Cestree/Ribbon depicted in various /tg/ franchises?
Give me a shout if you chose to to do anything Battletech related. I'm more than willing to help you out with any suggestions or answers to questions.