The first and original one is better imho. The second one is too dark and doesn't stand out on the default black background the of the device; and I didn't like the third one as much because it doesn't show the Time Geeks' craft.
Progress I think 3.0 shows progress, moving forward and all that jazz. Having said that though unless you've seen the first icon that sort of thinking is lost. 2.0 gets my vote - the 'time' effect is better. M@
Voted the second one. In my opinion is the best option, it shows the user that the upgrade has been made and it keeps the original`s design to which the users are familliar. Completely changing the icon should be mostly made in sequels not in updates. Good luck.
I like the second one's colors over the first, the third one is great too but it doesn't show as much. Voted for second.