Depends on how you look at it. This lens is a bargain compared to the 35mm f/1.4 offered by either Nikon ($1649) or Canon ($1329) especially when you consider that it outperforms them optically. On a high resolving camera like the D800, it's probably the sharpest lens out there right now, especially if you can place any confidence to DxOMark's testing:
DxOMark Lens Rankings [dxomark.com]
DxOMark Optical Metric Scores [dxomark.com]
As for how it compares to the Fuji, they are two totally different lenses. The Sigma is a full-frame lens, while the Fuji is for an APS-C (Cropped Sensor) camera. The field of view on the Fuji would be roughly if you were using a 50mm lens on a Nikon D800 or Canon 5D MK III.