This is an odd turn of events. With the films, I really didn't like the phase I helmet design, aka "the sad puppy", it was too narrow, the visor was too thin, and it just didn't do it for me. Meanwhile, the phase II looked better, good enough for me to buy multiples where the AOTC look I only bought a small handful.
Yet with Clone Wars, those phase I helmets all the clones were look pretty good, I like them. The helmets are wider and tapered more realistically, the visors are bigger, and the bottom of the helmet is sharper and doesn't have that impossible underside lip.
Last night was the debute of Clone Wars' phase II helmets on the ARC Troopers. I wasn't expecting anything outrageous after seeing the Hasbro battle pack of them, but in the episode I was surprised to find I didn't like them that much. They don't deviate far from the ROTS look, but the lines are slightly puffier, especially the area around the bottom where the vocorder and air connections are is closer together than on the movie version. Also, the cheeks cut into the helmet even more, and the visor and "mouth" are smaller. The ring around the base is an odd, bulbous shape, and the seams on the sides don't taper into that ring.
Compare this: http://starwars.wikia.com/wiki/File:...netrooper1.jpg
to this: http://starwars.wikia.com/wiki/File:ARC_trooper_TCW.jpg
(ignore the Fett rangefinder, and the top fin)