Japan Rail Pass: Green or Ordinary?

I will be in Japan during August, I guess some places are going to be crowded, like Kyoto.

Will I have any troubles (regarding reservations) if I use Ordinary Japan Rail Pass? Or should I buy the Green one? (I've heard that they are less crowded)

Thanks

On certain busy days during Obon you may have troubles making reservations. It is explained here:
http://www.japan-guide.com/e/e2286.html

On all other days, you should not have problems, especially if you make seat reservations a day in advance.

I recommend the Green pass only if you have the budget for some added luxury readily available.

I second that. The green one is just pure luxury. If you can afford it, then go for it. But I think you'll be fine with the ordinary one.