we purchased the land and essentially "signed it over to the builder" until the build was complete then he signed it back over to us in a cash deal the land would have reverted back to us after a certain time period even if the build was not complete

As a retired home builder, I'd want to know a heck of a lot more about the builder, his construction methods, and his suppliers before I even considered doing something like this. I'd want to see at least several homes during the construction phase to see the quality and the way they handle lots of details. Obviously there are some things I'd notice that others wouldn't, but general things like how they create the building envelope should be readily available so it can be discussed.

we've know our builder and his work for over 30 years we watched his last three builds at least two times a week before ours was built we've seen him have a framer dismantle a days worth of framing because of shoddy workmanship we were at the build every single day and if he didn't see us he called us if something major was happening he would let us know a couple of days in advance he only builds 2 houses at a time and the second house has to be out of the initial electrical and plumbing stages in the interior of the home before he starts another and he guarantees his homes (as far as construction goes) for 10 years so we were very confident in his work this is how he constructs every home

but you are absolutely correct ichabod you should know your builder very well before this method is employed

We are doing turnkey right now and know many others that have done the same without any issues.