I think it looks pretty good from most angles, not that great from a few, but you can say that about quite a few cars, even some exotics.
Colors make a big difference. Ruby Red (the darker of the two Reds), Ingot Silver, and Magnetic look great. White also shows off the lines better, but I hate white cars.
The brighter red, the yellow, and the orange colors look terrible to me.
Deep Impact Blue, Black, and Guard look meh.
Looking at some of the prelim design work that's made it's way to the internet, it's become clear to me that they were trying too hard to strike a balance between classic cues and modern looks (including Ford's corporate grille). To me, they should have gone all out on a fresh, bold, and thoroughly modern design.
Maybe the refresh in a couple years will incorporate some of the more aggressive elements from the early design concepts.
It certainly has traded its "iconic look" for the "FORD" look
2013 Mustang GT Premium Convertible
Candy Apple Red, Auto, FRPP Tune, GT500 Axlebacks, KONI Yellow Sport (adjustable dampers), FRPP Front and Rear swaybars, Custom Removable 4 Point Roll-Bar, BOSS 302 Low Expansion Brake Lines, Roush side splitters, GT500 spoiler, Redline Tuning hood struts,18" Ford Chromed Aluminum Wheels (9R3Z-1K007-A), Michelin Pilot Super Sports - 235X50X18
2011 Mustang V6 Premium Convertible - Gone