I have a Tanita with the "regular" and "athlete" modes, but find that the "regular" mode overstates my body fat, while the "athlete" mode understates it. However, if you take your measurements carefully (particularly with regards to your hydration levels), it is consistent over time, even if it's not "accurate".

FWIW, you might want to try the "Navy" body fat measurement approach. It requires taking a couple of body circumference measurements, and seems reasonably accurate, assuming you are careful in measuring. I've reviewed their research that went into the development of their formulas, and it seems like they put some significant thought (and taxpayer dollars) into it. Probably less accurate than the "dunk tank", but just as accurate as calipers.

I've built the Navy method into my CycliStats and WeightWare programs, or you can find it online at http://www.he.net/%7Ezone/prothd2.html .