I've flown all three, if I understand the options correctly:
1) United Business - non-stop from west coast
2) United Business - via an east-coast hub
3) British Midland "the business"
UA premium trans-con services are identical to their international services, so there's no real point in taking anything but the non-stop flight. You'll get a decent night's sleep as well, rather than having the rather short six-hour flight from the east coast.
The British Midland service is fantastic, and "the business" is leagues ahead of UA's business class service in every respect. Service, seat comfort, entertainment, and food are all vastly superior.
I flew one of the very first trans-atlantic flights on BD. My
trip report can be found on Flyertalk.
------------------
Please visit
The Mileage Runner's Toolkit and
Unofficial United Airlines Guide