3.06 ERA vs NL teams. You have to take into account the fact that he plays in the AL East. It's no surprise that you almost never see a starter dip below 3.00 ERA in the AL East. It's still arguably the toughest division to pitch in. Put him in an NL pitchers park and he'll enjoy a sub 3.00 ERA easy.
RIGHT NOW, I'm taking Lester over all of them except Kershaw, Felix, and Sale. The rest either haven't had enough sustained excellence (one or two good years isn't enough in my book. Promising, but if I'm looking to sign a #1, I'm taking the proven guy every time, money being equal) or have inflated #s due to the NL/etc. Price I think is a wash due to the unbelievable playoff success Lester has had, same with Scherzer and Wainwright. Tanaka, who knows if he can put together 4+ years of great pitching, we have yet to see that from a Japanese import.
You can put Lester where ever you want in that List, but in my opinion, there's at least a very good argument to have Lester in the top 4-10.