I grew up in WGC My parents are still there but I'm out of touch with schools I'm afraid. I found it boring as a teenager but going back now to visit, I've realised it has some nice parks and attractive buildings. It's also handy for London. Sorry not to be more help; I hope you get the info you need.
WGC can be beautifully green and charming in places, but on the whole I find it very sterile, made rather than grown, if that makes sense. My boss lives there with his family, and they love it. Schools seem to be alright, boss' youngest just started reception and they said they were spoilt for choice.
We're also considering WGC as an option. I think you might be better off reposting this thread in the Property or Hertfordshire threads for more responses.
We've only been to WGC once - just saw a bit of the centre, and don't have very strong opinions on the place yet. I like the number of green spaces but the shopping centre seemed rather soulless.
I understand there's something of a divide when it comes to housing. The 'West Side', which I think is west of rail line, seems largely well to do with lots of 500k+ houses. East of the tracks it's much more affordable. I'm still trying to get an idea about good/bad areas - have read in several threads that Knella road is to be avoided.
Would be interested to hear what you've found so far.