A/B/N testing is considered to be the most cost effective of all ways to measure page variations. The process of testing more than one page in a live environment allows for a high test velocity.
Benefits to A/B/N testing include being able to compare effectiveness of different styles in real time. The n in a/b/n refers to the number of tests going on at the same time. A/B/N is an extension of A/B testing except there are more styles being tested.
This testing allows businesses to know which one of the pages has the best impact with web users in terms of converting to sales. When companies cannot determine which website layout to go with they might run this test to determine which of a few options work the best for conversions. It will also show which style of page converts the worst and can help to discern what features make it unviable.
The only drawback is that it requires a larger sample size and thus higher traffic volume on the site in order for testing to be effective within reasonable timeframe.