Here is a comparison swatch of two different purple cremes by OPI.
Index and Ring: OPI Do You Lilac It? NL B29
Middle and Pinky: OPI A Grape Fit NL B87
The swatch above is three coats of each; however, A Grape Fit was opaque in two coats already. Its formula is a lot more pigmented and smoother compared to Do You Lilac It? I don't know why, but DYLYI seems to thicken up really really fast. Oh well, there's nothing a lil thinner can't fix. n_n
Different enough to own both? Yes, because they're practically two different colours! But for some reason I don't really like A Grape Fit on me, it doesn't seem to match my skin tone all that well and plus, it's really similar to another polish that I own. Then again, there's no such thing as owning too many nail polishes. ;)