The advantage to Nitrox is that it gives you longer bottom times or shorter surface intervals, for dives in the 60 to 110 foot or so range. By reducing the nitrogen you are breathing, it reduces the nitrogen loading in your tissues, and you therefore have a longer time at a given depth before you would require mandatory decompression.
Nitrox gives you very little on really shallow (2 ATA) dives unless they are extremely long. And it doesn't do very much for you on deep dives, because you have to reduce the extra oxygen to avoid toxicity, so the bottom time extension is not very great.
The minimum training to use Nitrox is a class which is purely classroom, and discusses the calculation of MOD and EAD, and covers oxygen toxicity and how to analyze tanks. It's not a huge time commitment.