What is Guangzhou like to live in?

Greetings to all,

I am a British graduate living in the UK and considering working in China teaching Eglish with (moderated:no free ads) They would place me in Guangzhou, train me for a couple of weeks and them find me a school to teach in for around 20 hours per week. Pay is between UKP600 and UKP950 per month, but they take 50% for the first four months. They refund my flight and visa costs upon completion of a six or twelve month contract.

What I'm wondering is whether anyone from a British, or more generally a Western, background who has experience of living in the city of Guangzhou in particular could give me a sense of how they found it. Was it an enjoyable place to live? Is there anything in particular I should know about this city before taking the leap? What are the upsides and the downsides?

Also, I speak no Chinese, but with regard to language preparation for just getting by in everyday life, should I start looking at Mandarin or Cantonese.

I'd be most grateful for any thoughts.

Best Wishes,
Longusername