loss of accuracy can occur in dxf's if the precision level is set low. All coordinates will be saved in ascii format with a fixed number of decimal places. If you work with very small numbers or very high tolerance dimensions in yor drawings, you could lose some accuracy.
You can control floating-point precision of the DXF format up to 16 decimal places. If that doesn't provide enough accuracy for your application, then dxf files will be less accurate.