Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Variable machine, variable quality

RCA perhaps indicates its opinion of their machine in that the RTD255 does not exist on their website -- no manuals, no information about it.The sound and DVD quality are quite good, when it works. It usually works.But occasionally when loading or unloading the mechnical apparatus just stops working. Mysteriously, if I cycle the power off and on, it sometimes starts working again. It is also -- as other reviewers have noted -- Very Slow at loading CDs and DVDs; and the MP3 picture viewing is so slow as to be worthless.The remote control is strangely designed; certain source types are not available on the remote.