There's a few differences between platinum and gold. Gold is lighter, I believe, but also less money, has more of a shine and you can get it in a few different colors. Platinum is more expensive and has a duller finish then gold (it's just the way the metal is). Platinum also kind of bends whereas gold doesn't really bend -if it's going to bend it just breaks!
I went with white gold for my engagement ring. It was really a cost issue but I love how shiny the white gold is. And the chances of it breaking are slim.
My jeweler in NY (it's a family jeweler my family has been doing business with for over 30 years) made the ring for us in 3 days. If you want his info just PM me - he's great!