I totally disagree with this one about designing and building your e-bike from scratch. The individual parts of a bike cost nearly three times what buying a ready made will. If money is no object sure.
I have played with the Raleigh mid drives and love them. The Hai Bikes are built by Accell also and are well designed.
There are a lot of e-bikes out there, they are not selling as fast as maybe the manufacturers hoped. I would bet there are significant deals out there. I would stick with the big brand names as parts will be easier to get. I would buy an extra battery right from the start.