It's hard to say since polish preferences tend to be so personal color-wise...
I've only been a subscriber since May also, and some of my favorites are the ones I got in my It Girl intro box: Helena and Mandy. Mandy, especially, is a color that is totally not me, but I fell in love with it anyway. Formula-wise, those are two of the most fantastic creme polishes I have ever tried.
I also got lucky with the Cinco De Mayo mystery box and got a bunch of polishes, although I ended up giving several away. My favorite from that batch was Taylor. I wore it again last weekend and fell in love with it all over again. However, it does do this weird thing where after about 3 days the color seems to fade and become a lot less vibrant (not sure if reapplying top coat helps; I didn't think to try it until it was too late).
Vanessa, the glitter top coat, is actually the one from my mystery box that I've used the most... I've used it in probably over half my manicures since, usually for accent nails. It's a lot of fun and the periwinkle glitter in particular is unusual and awesome (though it's tricky to find a good base color that works well with it). It goes on fairly easily but, like any glitter, it's a pain to remove.
I also got Marisa in that batch and although I've only swatched it because it's too dark of a color for summer, I really liked it. Formula-wise definitely a lot trickier though; kind of thick and goopy. I'll probably thin it before I try to wear it.
