If you mean the D-wave devices specifically, the kerfuffle is that the low-clockrate quantum device does not complete tasks any faster or cheaper than a compara

If you mean the D-wave devices specifically, the kerfuffle is that the low-clockrate quantum device does not complete tasks any faster or cheaper than a comparably priced classical computer, and the open question as to whether they can ever be made to operate faster. That's why there's only research labs buying them. But the device does work.