I've hesitated for quite some time, unsure of spending almost 200euro on a dibox. In the end, I've decided to buy it on order to connect my keyboard to the mixer. I'm really glad I did so:
1. it is built like a tank
2. the sound is warm
3. the ground lift alleviates any hum --> no more noise on the stage due to other electrical devices
4. being stereo it is great for keyboards or other stereo inputs (computers, music playback, etc.)
5. no risk anymore for my keyboard to be damaged by phantom power, faulty mixers, etc. A friend of mine had his Korg PA4X mainboard damaged because of a faulty mixer!
Maybe you'll think it is expensive but please remember that quality transformers and components come at a price!