If we're still talking about about about Jenas, well he was one of those players who had a bit of everything. He could pass, run, dribble, tackle, shoot, take free kicks, stamina, he was a complete around player....the problem was he lacked confidence in his own ability to be the best...and that's why he was always on the periphery of being a great player. Good enough to get in the England squad, but not be in the team. Good enough to play in a Spurs midfield regularly, but not at ManU. He could comfortably support players like a R.Keane or Berba or a Lennon, but never be confident enough to show he could be the best player in that team. To really be the best you need a bit of inner arrogance and selfishness to show you are the best. I think he was happy to show he was good enough, but not confident to show he could be the best. As someone else said Spurs at the time was probably a safe place for him.
If you really watched him and Gerrard the main difference was that confidence and arrogance and desire to be the best. One believed he was and the other didn't.