I don’t have concise precise answers for you, currently. Still figuring out as well. Speeds are still being explored by people. Quality, speed, size and cost will vary depending on parts used, build and assembly approach/quality. For example, my assembly won’t be as precise as other folks, so am unlikely to get the numbers they’re seeing.
We do know these can be built cost effective and reliable enough machines to run at least one CNC business, likely other people’s businesses too?