I'm a big fan of Habana - but I'd rather have Jane on the right wing at the moment. Habana would be better on the left. In terms of form - there isn't much in it.
Habana has had a much longer career than Jane. He debuted for South Africa in 2004, has played 83 tests and scored 47 tries (try scoring ratio of 0.56).
Cory Jane has debuted in 2008, has played 41 tests and scored 16 tries (try scoring ratio of 0.39). So yes, Habana is a more prolific try scorer than Jane (Jane certainly has many other qualities).
Shane Williams debuted for Wales in 2000, played 93 tests and scored 60 tries (try scoring ratio of 0.66). His tries is the third highest of all time and the highest in the professional era from a tier 1 side. I think Shane Williams will certainly go down as a legend. Of players who have scored at a higher ratio than Shane Williams, having scored 30 or more tries are Daisuke Ohata (who I don't really count), Doug Howlett, Hirotoki Onozawa (same as Ohata), Christian Cullen, Jeff Wilson, Joe Rokocoko and Sitiveni Sivivatu.
I think Habana will go down as a legend - especially if he has another World Cup left in him as he may overtake Lomu as the most tries in World Cups (with 3 world cups as opposed to 2).