I called 2 years ago at exactly 6:59am and was lucky enough to reserve the one and only boat, the Breathless, for our EPCOT Illuminations viewing. That boat always gets front and center.
2 years ago it was $175 and seats 6 of 7, there were 6 of us.
There is a great article about it on Deb's WDWIG site. It is a speed boat. No food or drink allowed on this nice boat though.