OK, two problems here. The first is that the "2" in 20 cents has a red smear. Not too odd, but I have two identical. Is this common?
Of more interest is the shading in the bottom two hearts. On all of my other copies, the blue and purple heart are just like all of the others in that they appear to have a speckled appearance. In one of my stamps, they are definitely "cleaner" without any of the speckles. I hope the images do them justice.
The stamps:

The odd "2":

The speckled and the solid hearts (only the bottom two -- blue and purple). The speckled version is what I consider "normal":

Solid hearts:
