The data look basically as expected:
Streamlines stringently constrained within WM and SGM due to the use of ACT.
Spatial distribution of streamlines density (gauged by the amount of “empty space” in between the streamlines) is approximately equal across the white matter; this is not explicitly a constraint in SIFT, but tends to be what the FOD data suggest, and also makes sense from a physical perspective (if one can fit a certain density of fibres within a given volume of white matter in one area of the brain, why would the density of fibres be grossly smaller or larger than this elsewhere in the WM?).
The low-ish b-value means that the interpretation of FOD amplitude (and concomitantly streamline count post-SIFT) can’t be interpreted as being proportional to intra-cellular volume / cross-sectional area with confidence… but applying SIFT nevertheless is likely still preferable to omitting that step.