here's my take from doing all of these this year (granted almost all AA/BA due to points):

virgin upper class: excellent ground experience and superb lounge. if you can snag a seat in the 744 nose, great. i'm very tall, so i find the seat limiting. service on board, excellent for business. food/drink the best of three.

american biz: industry-leading seat. no question. very comfortable and excellent entertainment. lounges are sad (unless you can use the BA lounge w your status), service on board is a mixed bag, though i've never had a reason for complaint--they are always pleasant to me. but the food/drink? the worst of the three. just terrible compared to the other two options.

ba biz: love it because i can still fly the 744 on UD in club world. i find the seat perfectly fine. not as good as AA, but i like it more than virgin. service has been traditionally perfect and friendly. food/drink second behind virgin. plus i like flying backwards!