TJH I'm in your same situation and I got my ideas about the schools through the web so what I'm going to pass you is not coming from my direct experience.
If you will keep surfing the webfor more information you will find out that ISL has many people reporting bad experiences with them while I haven't found anybody writing something even slightly denigrating the compass school. My banal assumption is that there will be a reason for it ......
Good Luck though to both of us !