I can't find much to criticise for this DI. I bought this for stereo line-level sources like keyboards and synths. I prefer it to active units because for high peaks or hot levels it is much nicer than an active DI in clipping. Has a noise and distortion-free sound, very clean. Extremely well built, very rugged. Has all the necessary features and is very versatile. The transformers have a slightly different sound to Jensen but you won't notice until it receives a very high level and starts to break up. Then I prefer this one because the Jensens in the JDI can be slightly bright.
This DI is especially suited to stereo line sources; if you require a L-R merge function or a mono DI for amplified speaker outputs from an amp, Radial have better alternatives like JDI passive or J48 active, which is why those features aren't present. This is perfectly suited to stereo keys, backing tracks etc. No loading problems driving long lines. Excellent simpler and cheaper alternative to JDI stereo and others, definitely better sound and build quality than cheap passive DI's. Great value for a true professional unit. I just wish it had 2 of every switch and function so you could use it as two completely independent DI's for 2 mono sources; there is only one earth lift switch for both inputs. It's designed for a stereo source but can be used for 2 mono sources, with that slight limitation