Vantaggi
The other teachers were very fun and supportive and were great to be around. They really helped form a good social group and were always accommodating with questions and help. The Korean staff were sweet and the manager does try to take care of you. The accommodation is decent. The kids can be hard to manage, but overall are charming and fun to be around. Adult classes tend to be more relaxed and you will have more autonomy over them, making them quite fun to teach.
Svantaggi
I'm concerned that one of the positive reviewers here has insinuated that the negative posters must be teachers with unrealistic expectations of teaching. I suppose stability in classes and hours, transparent and reliable pedagogic practice, as well as decent holiday hours are unrealistic expectations of working in Korea. Before I address WILS specifically, I want to add a few cautionary words about Korean culture, especially with regards to private education. Mok-dong is mostly an affluent neighbourhood and many middle-to-upper class families reside there. This translates to a heightened sense of entitlement that students and parents would not usually display in public schools. In a hagwon, parents are paying for the services, and therefore feel free to make demands that seem over the top, both of their children and the hagwon teachers. You might be asked to give students more homework as well as potentially be held responsible for a student's academic progress. Korean society is generally extremely competitive, and hagwons must cater to parents who are their most valued customers. Therefore you will most likely be asked to teach in a style that may not indicate actual learning (according to research), but demonstrates an increased output (e.g. homework pages). This is quite difficult for students who often go to multiple hagwons and have stacks of homework to do by the end of the day. You will often have to delicately balance these standards with trying to make your classes fun and engaging for kids who may be (understandably) tired and demotivated. Which brings me back to the question of WILS. If the hagwon adhered to a certain pedagogy and certain curricula, it would be far easier for the teachers. However, in my experience, books were often changed (as well as classes) mid-term, teachers are expected to somehow provide bespoke educational services to every single student, and you're often messaged with requests to do extra classes the night before (or even the day of). That WILS is a small or 'family-run' hagwon should not be justification for the distorted and hectic way things are run. I've talked with Korean friends who are very surprised at the conditions I've described and told me there are smoother-run and better hagwons out there. Moreover, the high turnover of Korean staff and the stressful conditions they work in remains a bright red warning flag. If you thrive on chaos and find the element of surprise indispensable to your work-day, this is the place for you. And (it must be said), Korean society is still very conservative, and the parents who pay for hagwons seldom deviate from the idea that the best teachers of English are white and male. If you happen to tick both boxes, you will generally be treated with more grace than otherwise. Vacations are unpaid and if you take time off, you are responsible for finding someone to cover your classes. This means preparing the material in advance for the other teachers and can take up a lot of time. Time for preparation and filling in reports are not paid, and you can often spend quite a few hours doing these tasks. I wouldn't recommend WILS for novice teachers, as yes, you will get flexibility on how you teach your books and a certain measure of autonomy that 'chain' hagwons won't allow, but you won't get the support novice teachers need during their first year. I would also recommend checking out other hagwons and messaging other teachers at those hagwons to make an informed decision if you are thinking about teaching for the first time in Korea. I think the WILS atmosphere is better suited to teachers with a few years' experience of teaching in Korea and who have an engaging class presence.