When I went (May - July '13) the job and environment had been very much misrepresented. This made for a lot of frustration and dissatisfaction. There were two main organisations (one in Quito & the other in Machala) who organised the volunteers. The poor communication between the two made it very difficult for the volunteers. However, they had made some improvements by the time I left and some of the volunteers had put a huge amount of effort into improving this.
Machala's population is about 200,000. There is little entertainment, unless you're into very noisy night clubs.
So be prepared to travel usually at least a few hours for entertainment and sight seeing on the weekends.
Females it is a very difficult culture. If you show an interest in the men and they like you, be prepared to be harassed by them. Local females take great pride in what they look like so be aware you will be constantly looked up and down. They don't say anything but it does get annoying.
We were strongly advised not to walk around Machala due to safety reasons, but many of us did without any issues. However, Puerto Bolivar (more like a suburb of Machala) is dangerous and it is very risky to walk around. So much so we had a driver pick us up from our homes and drop us at the school gate, even waiting outside the school gate was not acceptable.
The drivers were great but with only one and a group of volunteers punctuality is not possible even though they try really hard.
Actually punctuality is not a priority at all in this area so don't be surprised if you are kept waiting for very long periods of time for anything and everything. My advise, always have something to keep yourself entertained while you wait.
I was placed with a lovely family in a beautiful house in a safe neighbourhood but I was very lucky. Accommodation can be very hit and miss whether is it is in a hotel or home stay.
Teaching between 34 - 40 kids in a very noisy hot environment (there is no glass in the windows) with very limited resources is very challenging but can potentially be very rewarding.
The more Spanish you know the better, while you can get away with knowing little when teaching English. It makes everyday living so much easier and more interesting, especially if you are going out with your host family (they spend a lot of time socialising at family and friends places).
I definitely recommend visiting some of the attractions Ecuador has to offer instead of just doing the volunteer programme. I went to the Galapagos Islands and the Amazon (you need a bit of time to do these and money) and they were both awesome experiences definitely worth doing. Both are such diverse places, and doing them after the dreariness of Machala was even better.
While over all I didn't enjoy my experience in Machala but I don't regret going, I certainly learnt a lot about a country, culture and myself. I had different experiences on a daily basis, every thing from bad to awesome, confusing and funny. Definitely an adventure.