I went through two winter season's with Nitrogen in the tires. I was told it would be more stable. My issue was when our weather changes, Fall to winter, winter to spring I was always getting a low pressure tire warning light. The first change , Oct, Nov, Dec I was fine, no warning light but that spring it came on again. Following weather change I got lights so it is apparently the same as air. We also found that it fused metal caps to the valve stems. The fix for that is to use a silicone spray, loosen them and tighten occasionally and if you do get one that siezes up carefully heat the cap with a cigarette lighter and unscrew carefully. We went through this on my daughters Audi. the shop literally ripped one of her stems off with pliers trying to get a cap off then tried to charge her for a new stem. I had to show them how to remove a seized cap and then told them we were not paying for their service reps negligence.
I am back to air in my car now. The trouble it takes to find someone who has nitrogen if you get a light is a real PIA, air pumps are at almost every gas station. Nitrogen is no better than air. My 2 cents on the subject.