Glass bottom boats to see turtles - details please!

[StaceyCT]

I'll be traveling with two other adults and my two year old son and would like to take a glass bottom boat out to see the turtles and shipwreck. This way, two adults could snorkel while the other adult and DS could still see the turtles and fish through the glass bottom of the boat.

I've read through several threads here that indicate that glass bottom boats are freely available for hire at Paynes Bay. I still have questions:

Can you really see well through the bottom of the boat?
Are all the boats and operators of similar quality, or is it hit or miss?
Do the boats manage to avoid the big crowds of people who are drawn to the turtles?
Would there be an advantage to going from Folkestone Park as opposed to Paynes Bay?
Does anyone have experience with the "Sea Eye" hydrofoil (sounds like a super-duper glass bottom boat)?

Thank you!