Re: Is Berdych's style really similar to Del Potro's and Söderling's ?
They are similar in regards to some things, not to others. This is trivially true of course, but my opinions as to places where all three are similar is as follows:
Height (this is the only one not up for debate)
Power (whilst not equal in this regard, in the countext of the whole tour, they are surely in a bracket of 'power' players)
After that, it may start to break down. For example, in terms of patience, I would say JMDP >> Soderling >> Berdych. That is to say, JMDP is most willing to engage in long rallies, Berdych least. Soderling can do either, his power game dominates many weaker players and at his best we've seen him comprehensively overpower Ferrer on clay and even did the same to Federer on clay (though in a much closer match). However, when it's needed, Soderling plays long rallies. Watch the London match between JMDP and him, a lot of long points because neither player was giving up a lot of space.
JMDP is the best defensively imo, not to say necessarily the best mover but certainly the best in a defensive position on the forehand side. Berdych is worst defender imo, he has decent movement but usually only wins matches he is the aggressor in. For example, when Federer has played him, he has won or come very close to winning when he has dictated play, lost otherwise.
There is much more to say about these three interesting players, Berdych is much the most 'natural' ball-striker. Quite what I mean when I say that is hard to state but it is exemplified by his easy power off the forehand especially. JMD is powerful, but mainly because he absolutely smashes the ball. Soderling also has easy power but to me it looks a less technically proficient stroke.
Champions deserve whatever they win playing within the laws of the game