First, are you a teacher or a student? It really isn't clear from your post. In any case, I think you need to narrow the field a bit - the world's a big place. Did you have a particular country or city in mind?
Note that while a school might use the Speakout series for one or two levels, they are unlikely to use it across all levels, not least because there are six books but most schools have seven to nine levels for adults. Furthermore, schools have a habit of changing their coursebooks from year to year, so I don't think it's a good idea to choose somewhere based on the books they are using now. A teacher who can/will only use one series of books isn't an awful lot of use. I've worked in over seven schools and have used at least four different series of books in each one.
Finally, online classes are usually private ones, meaning that you can use whatever book(s) you want to. Be advised though that no one series of books works for every student in every situation - you really do need to vary the materials you use.