Standard Galaxy S4 with a Launcher Vs. Google Galaxy S4

I'm asking this question because to be honest I don't really know all the pros and cons...

Forgetting price and just comparing the phones as they are, what is the real difference here and which one would you choose?

The reason I'm comparing a standard S4 with a launcher is because if I get the standard version the first thing I'll do is stick a launcher on it to get rid of the unsightly TW screens...though I realise that's only a skin deep solution.