(I'm sorry I have no fancy photographs. Some toddler that lives in my apartment hid my camera.)
The Milani was the first to chip, not because of the polish, but because I slammed my finger in laundry room door and split my nail in two. Amazingly, this had no real effect on the polish itself. It wasn't until the dead bits of nail started flaking that the color started flaking off as well, about 2 days later. So the Milani lasted 3 days. Had I not had the unfortunate accident, it may have lasted 4. Milani tends to tear off. Once the flaking begins, it only takes a few hours for it to look jagged and icky.
The Sally Hansen Xtreme Wear was the second to chip, later that same day. I had a teeny rough spot on the edge of my nail and when I tried to smooth it, the polish peeled off in one big chunk. I guess it depends on how you like your polish. If you'd rather it come off all at once, this may be your brand.
Throughout the first three days, the two professional brands began to fade. That's right, not chip, fade. When I first put them on, they looked okay. Now they just look crappy. I'd say leave the professional polishes to the professionals.
On day three, I needed to push back my cuticles. This resulted in a lot of chipping around the bed of the nail. Having already caused the damage (and because I have nervous compulsive issues) I decided to attack the polish full force. The two brands least effected by my attack were the Revlon and the Sinful Colors.
The Sally Hansen Hard as Nails brand ended up peeling like the other SH polish, but it did last a bit longer.
The Maybelline Fast Dry and the NYC in a New York Minute performed impressively, in that they did not chip until actually attacked. After that, they did not chip much.
The Wet n Wild is probably the heartiest of the fast dry's. Despite the fact that I tore my nail yesterday, the only apparent chipping is at the bottom where it came into contact with my cuticle scissors. This polishes biggest downfall is that it comes in a limited array of colors, most of which are metallic. I've found, metallic polishes take longer to come off. Great when you want a good manicure. Bad when you want a new one.
I believe that for now I shall declare Revlon the best. The polish did not fade, nor did daily wear and tear take off much polish at the nail's edge. It even persevered through my cuticle cutting and subsequent attack, leaving me with a nail that still looks almost perfect.
Sinful Colors comes in a close second. Although some fading is apparent and difficult to dry, it is chip resistant once cured, and would still look perfect were it not for the smudge I got on it on day 1.
Third is a tie between the Wet n Wild and NYC fast-dry brands. Neither chipped too terribly, though I doubt they would last much longer.
And those are my experiment notes. I plan to make a chart to determine which polish has the best qualities. I'll get back to you on that in a few days.