Berdych is a scary good player when he's on. He's one of those players that, when I watch him play, I wonder why he hasn't won more tournaments, even a Slam or two. And, unlike say Ferrer or Tsonga, he went pro at a very young age - his only ATP 1000 was won at age 20. But then I watch a little longer and he almost invariably implodes and I realize why he hasn't won more.
Actually, his year-end rankings paint quite a picture. He was ranked #113 at age 18, #45 at age 19, #24 at age 20, and then #13 at age 21. One would think this was an elite player in the making. But then he stagnated, finishing age 22 at #14 and age 23-24 at #20. He's finished his age 25-28 seasons (including this year) #7 or higher, but for some reason was never able to take that next step up into the true elite.