Yup very often two HD3850's will = a GTX. Not always and you need a mobo that supports crossfire. http://www.anandtech.com/video/showdoc.aspx?i=3151&p=10
But otherwise for a year now ATI has not had an answer to the 8800GTX. They have competed very well in the sub $300 range, but been behind in the high end since G80 (8800's) were released.