Glad I did it

The first thing to note is that your experience will vary widely depending on where you are posted, something you do not get much choice about. Mine was with a fairly large group on a proper campus, which was good, but also there was not much to do locally. The length of the programme also affects how it goes - two weeks was more than enough for me, and a two-month programme will be very different.
The teaching was fairly straightforward but hard work, everyday I had to draw up lessons plans and then deliver the lessons, in English, general British culture and in food. If you like teaching or want to teach, you'll enjoy it.
Yangshuo was the highlight of the trip. While it is a relatively sort stay (4 nights, often 3 days), it is very lively and social and you get to meet lots of other gotoco people. However, it is not much of a reward compared to what you get on other programmes, where you are often paid a lump sum.
Like similar programmes, it does provide a start (or end) point for travelling more widely in China, which is brilliant.