How does a Nikon 85mm 1.8g act on a D5100?

I love the quality of the 85mm however the camera I have (D5100) has a crop sensor. Anyone use the 85mm on a crop sensor? And how did you like it? I'm in between the 85mm and the 50mm (both 1.8g with AF) for portrait/event photography. I don't want just head shots so I'm kind of leaning to the 50mm now even though I was just in love with the 85mm. Also, how are the pictures with the 50mm on a crop sensor?

Lenses do NOT "act" and they are inanimate objects so love probably is not a factor.

A prime lens like a Nikkor 85 mm lens provides an angle of view associated with portrait photography (28°30' when mounted on a full frame camera). Mounting it on your DX camera, the angle of view will be narrower. This is why many people use the 50 mm lens on a DX camera (31°30' -- close to the 85 mm on an FX camera body) so they do not have to photograph people from across the room to get more than a head and shoulder shot of their subjects.

Both lenses are suitable for portrait photography. I typically use a 24-70 mm f/2.8 at 70 mm when shooting portraits using an FX camera or at about 55 mm using a DX camera body.

Here is a link you can visit to see exactly what the 85 mm lens will:"see" when mounted on your D5100, DX camera

The 85mm f/1.8 on a DX camera will have 1.5x stronger focal length, and produce 1.5 stops more depth of field.
Therefore the 85 @ f/1.8 is equal to using a 127mm @ f/2.8.