Are you talking about the new FastFind or the older FastFind? Unfortunately McMurdo kept the same name even after they drastically redesigned the unit, go figure.
The newer FastFind w/GPS (technically known as the FastFind 210) has a 50 channel GPS receiver. I own one of these and am happy with the price, size and weight. I can't say how it will perform, but based on this initial evaluation by Doug Ritter (with more scientific testing than any of us normal Joes could do), it seems good enough. The best part is the one handed, teeth bite hand grenade deployment.
http://equipped.org/McMurdoNewFastFind.htm