Concept: 2 out of 5
Execution: 2 out of 5
Yeah, but: It could be better - but how?
The Long Version: The Sony PCM-D50 is a great audio recorder, tough with good sound quality. One of its nifty features is a five-second preroll buffer, meaning that it can capture sounds that happen when the recorder is running but paused. All you need to do is hit the 'pause' button without spoiling the recording with handling noise, and that's where having a remote comes in.
The RM-PCM1 is a simple little device, being a thin remote on an equally thin 6-foot long cord. It has buttons for pause, record, stop, and divide, and a light to show when the recorder is rolling. Simple, straightforward, and does everything needed to control the recorder during capture. It even has a right-angle connector, which I love.
But despite its seeming usefulness, the RMPCM1 remote isn't an easy recommendation. For one thing, it doesn't really feel like a Sony product, certainly not in the same league as the D50 and D1 recorders that it mates with. The cable is thin and slightly insubstantial, leaving an expensive accessory feeling almost cheap. The other issue is that it's something of a nuisance to use. The six-foot long cord is too long to use while close enough to monitor the levels, and if you want to monitor the audio from the end of the remotes' reach, you'll need an extension for your headphones. Using a reliable radio-frequency wireless system would be a huge improvement, even if it adds to the already nontrivial cost.
So get the PCM1 remote if you'll need to be able to control the PCM-D50 or D1 from a moderate distance, or if the preroll buffer is an important part of how you'll use the recorder. Otherwise, give it a pass - it really doesn't add anything for normal use.