what a co-incident! I just bought a heart shape diamond last week! mine is 1.61 ct, E color, VS2, GIA.... I like lower length to width ratio (around 0.92 - 0.95) as I love "fat heart" and it looks bigger for the same weight . see this link if you don't get what I mean
As many sis mentioned above, heart shape is more on "合眼緣" and proportion of heart so don't buy until u try it on.
I just have the simple four-pronged setting as my hubby doesn't like a lot of 碎石 that's distracting (I do like that kind of fancy setting in fact)
The shop owner told me the singer Lee Hxxkxx just bought a pair of 1 ct each heart shape rock (S1 E color) for ear-ring.... that's really lovely. I think for ear-ring, can take lower clarity (if you are not a perfectionist) for bigger size / brighter color