Been in Goring/Worthing for 3 years now, having lived all over the place.
I love it down here, the air is like nowhere else. I've just got back into biking and as it's only a few miles from the downs...
what's stopping you??
As for the chavs?..it's very rare you can find a place without, and even more pricey
The commute will take you a bit longer than from Brighton, but not by much, although i would look at how much the train tickets are going to cost you. Brighton/Worthing to London could be a deal breaker.
I would definitely recommend Worthing over Brighton or Hove, much less busy, crazy and dirty, also less expensive. I don't know too much about Shoreham or Portslade, but i would hazard a guess and avoid Lancing.
Hope that's been of some use!