Routing speed: For those with the official devices, it should be easy to test the performance on the same hardware. Although, note that storage speed may play a role here.

Our routing (offline and default online) is provided by Valhalla. So, if we see some strange / slow results, we can file the issue upstream. In this respect, we actually have backing of dedicated developers working on routing engine.

The last time I benchmarked, OSMAnd was slowest, Maps.me was the next from the bottom, and OSM Scout Server was roughly similar to HERE and they both were the fastest.

Earlier, Pure/WhoGo/Poor Maps was asking for geocoding info together with the route at the same time. All the other apps mentioned above, were doing geocoding immediately while you entered the address. As a result, it may have seemed that osm scout server was slower - it had to resolve addresses first.

These days, Pure Maps finds coordinates of origin and destination as soon as you enter them. You , behind the scenes, are not even entering an address as a point, but location coordinates. That has many advantages and, as a side effect, benchmarking should be easier now.

As for simplicity of the interface, Maps.me was always simpler, indeed. But I must say I haven't really used any of them for a while, just occasionally checking when thinking about interfaces and workflows.