Both are good recorders. Which is better depends on how you plan to use it.
The R-09HR is smaller and cheaper than the D50, can record in MP3 format, has an internal speaker, and uses less expensive SDHC cards. The R-09HR can handle louder sound without clipping. Edirol includes a desktop stand and a wireless remote control for the R-09HR, while Sony charges extra for these accessories.
The D50 wins in just about every other way: better preamp, better battery life, better construction, digital input and output, pre-roll buffer, 3 positions for built-in mics, 4GB of memory built in, and so on.
In some cases the difference between the R-09HR and D50 is small. For example, plenty of people here are happy with the R-09HR's preamp for concert recording. The Sony's preamp is quieter, though.
Here are Guysonic's test results that show preamp noise floor for mic and line inputs
http://www.sonicstudios.com/-35dbu_n.gifhttp://www.sonicstudios.com/-35dBLOG88.2vs3SXpip.gifAnd here is Raimund Specht's page showing his measurements of noise floor
http://www.avisoft.com/recordertests.htmThis last set of tests shows that the R-09HR's preamp can handle about 15 dB louder sounds without clipping. In some circumstances, you would need to set the Sony to record at low mic sensitivity, or perhaps run an attenuator with your external mics.
Flintstone