I recently did something similar, I had 9 hours in the pool over the weekend for £250.
I began with the ability to stop myself drowning and worked up from there, as it's a different way of swimming entirely I didn't make as much progress as I initially hoped for but with the book/DVD all being well it'll work out in the end.
Was it worth it, probably, certainly if I can continue to teach myself the final bits as it appears a good technique. I guess I'm a little too impatient though and wanted more obvious results there and then.
Good luck! Feel free to email me if you want a fuller description of what went on...