Slow or not is really subject or where we come from.
It certainly OK compare with human.
If I start with SDS100, I won't say SDS100 is slow. But coming from, say BCD436HP, with expectation that SDS100 is the next generation scanner, it is natural to feel like a downgrade in this area, and from pragmatic reality I do find SDS100 fails to pickup as many active channels (especially analogue ones, using DND) due to SDS100 is lurking around inactive one longer (again I tried different filter). We can argue SDS100 is SDR based blah but it does not help on slower scan fact (see, I hesitate to call it slow).
The experience is also site dependent. in area where I live (crowded & busy communication), even just monitor P25 only has so many interesting channels I'd like to monitor, the slow scan is more pronounced than to some people living in a calm and peaceful town with moderate traffic.
I have no plan to discard my 436HP after aquire SDS100, just as I have no plan discarding the BC125AT when I picked up 436HP, as the latter is unbeatable (among Uniden scanners) for airband etc...
I appreciate people help on how to improve SDS100 scan speed. But not expecting drastic change.