Radial DI-boxes aren't cheap but they are really sturdy pieces of equipment that gave me very good results in the studio. They are probably one of the most expensive DI-boxes out there and I am sure that a decent percent of a price is just the fact that you are getting a product of Radial Engineering.
JDI Duplex is based on JDI Stereo DI-box. It is equipped with Jensen transformers and unlike Radial JDI it offers multiple input connection possibilities: XLR, RCA, 1/4", and 3,5mm stereo input. I needed a DI box in the studio for two stereo devices that I do not use simultaneously and one of them has XLR connectors and JDI Duplex serves this purpose very well.
Plenty of people would think that you could plug many instruments into JDI Duplex and use it as one DI-box for more than one instrument. I have thought the same thing but there is something to be aware of. First, if you cannot use other input connections while using XLR input connection. There is a switch that activates XLR connection and deactivates 1/4", RCA and 3,5mm stereo connection. Second, you can use all other inputs except XLR simultaneously but keep in mind that JDI Duplex isn't a mixer. It might happen that the signals coming from different sources into two different inputs will not be equally present.