FYI, I met somebody this past week that was put on the RMP list on Thursday, and went IRR the following Monday with no adverse remarks on fitrep. I believe those who say it's explicit in the instructions, but it doesn't seem like it's followed. That said, the IRR is not going to do your career any favors...
It's all relative. If you're career is making big bucks on the civilian side and being home on the weekend while you do coloring books for points, it can do wonders for your career.