Lensbaby

I'm looking into getting on of these to do something a bit different with my photography but I don't know the difference between the glass and plastic other than this:-

Plastic optic version for a dreamy look.
Double Glass optic for a tack-sharp image.

Does anyone have either of these and have some example images or why you chose one over the other.

You could PS the glass version for a dreamy look.
You cannot PS the plastic version to be tack-sharp.
Then again, I don't think you can PS the glass one to be tack-sharp either

I don't own one so I could be wrong.

The Double Glass Optic comes with most models. So you kind of get it first. The Plastic Optic you can get later.