I do not think that Lester is much better than his ERA shows he is after a review of his peripherals. I am only going to do this once, so here goes. I compared Lester's ERA to the pitcher with the median ERA for pitchers who have thrown at least 60 innings this year with a similar pitcher in terms of ERA, in this case Phil Hughes to see if Lester's peripherals were out of line. I also compared this year with Lester's career numbers. I did not use Babip as I do not think this is a particularly useful stat.
The stats, in order, are ERA, WHIP, K/BB, ERA+, HR/9, and WAR.
Lester this year: 4.53/1.367/2.78/93/0.8/-.1
Lester (career): 3.62/1.297/2.49/124/.8/3.27
Hughes this year: 4.48/1.297/3.86/93/2.0/.8
Hughes' numbers are not out of line with Lester's. He has allowed more HR/9, but his K/BB and WAR is better. His WHIP and ERA+ is identical. I conclude that based on these stats, Lester is NOT better than his ERA indicates, though more players could be analyzed this way to better substantiate that opinion.