I know of lots of mums who used C&W instead of St G's even when they live right by St G's!
I've had two wonderful births at St G's (one in Carmen, one induction in delivery suite) and excellent maternity care even with a few complications involving lots of extra appointments. But wouldn't have considered travelling to one further away anyway.
When my partner realised there was a choice (after I had chosen St G's) he couldn't believe I didn't choose C&W because "that would look so much better on their passport as place of birth than Tooting"!!
That said, it is wonderful we do have the choice- even if we decide only based on which one sounds better!