Having just watched the Australian version of "The Slap," I was interested in seeing how the US version would compare. It was quite a disappointment.
The Australian version was cast much better & key story elements were developed much better as well (for example the tension and chaos building up to the slap was perfect in the Au version, but completely unbelievable in the US version).
Regarding Casting: Jonathan LaPaglia, who plays Hector in the Au version is a much better fit. Also Alex Dimitriades as Hector's Cousin Harry in the Au version is a much better fit as the sort of short tempered hot- head.
There are many great actors in the US version- but they are unfortunately either cast in the wrong role (in a few cases) or do not work for this series at all (most cases). Thomas Sadoski is a talented actor, but is an example of miscasting. He could have been a decent fit as Hector, but not the correct fit for the role of Gary. Peter Sarsgaard and Zachary Quinto are also talented actors, but do not work for this series at all.
I guess I have to also question the directing. The entire initial episode was completely rushed, disjointed, and simply not believable. (Case in point- the tension between Quinto & Sarsgaard seemed almost joking rather than heated). I think both are good actors, so the problem is likely one that falls to casting or directing?
There are many other problems I could mention but suffice it to say- If you are at all interested in this series, skip the US version and watch the AU version..... Or at the very least, watch the first episode of each and see if you agree (It will only take 1 episode of each to make up your mind).