Originally Posted by Soju

Based on this information, forget about UA's MP program as your miles will likely expire before you can build up enough to use them, being they expire after only 18 months. I'd recommend OZ unless someone can recommend another FFP where the miles don't expire. Based on your booking class, I think OZ will give you 100% of the miles, but regardless of what percent a FFP gives you, if you can't use the miles before they expire they end up being worth nothing to you. Stick with a FFP where you can go for years without traveling without worrying about losing what you've already earned, then later in life if you find yourself traveling with more regularity review your FFP and see if there's another one that might suit you better.