I have taken Jamboree and it is a complete waste of time and money. They do not provide any counselling. They just give you a list of schools based on your profile (which is actually all schools in 2nd and 3rd tier if you have a very good profile) and do not even help you with ways to improve your profile/essays.
Their essay writers are all editors at various publishing houses and are all part-time. They also run their own essay writing services so, overall, they make no attempt to spend time to understand and improve your profile. I dont mean improve -- they wont even tell you some of the things on your profile are worth high-lighting.