All the talk of Ironman makes me feel old to be perfectly honest. Now that I work full time I don't have time to play games for 12 hours and then lose and have to start over. I wish I was young again and had all the time in the world for games. Alternatively I wish I had been born rich and never had to work a day in my life. Oh well. I'll stick with normal Classic.
Think of it this way. The original UFO/XCOM lasted people nearly 20 years. You also have years to play the new one. It's not going to be obsolete in a year, unlike a CoD or Madden game.