I think the DA 70 is a good lens, but I wouldn't say great. I think for me personally, it is a focal length that I don't particularly connect with . When I am shooting, I tend to reach for the DA *55 or for the DA *50-135, rather than the DA 70. I have seriously considered getting an FA 77, but mainly for the possibility of using it on a film camera...
I think the DA 70 strong points (versus the FA 77) are faster auto focus, smaller size, and a little stronger borders wide open. Obviously its weakness is it smaller maximum aperture and bokeh isn't quite as good (its not bad, its just not quite as nice). Both are good lenses if you like that focal length.