Crossing into Cambodia from Thai very soon. I'll have about 3000 baht in my pocket and wondering if I should exchange that for US$ or Cambodian Riel. May only be in Cambodia for 2 weeks but think I'd get to spend the Riel although I also wonder if US$ are used so much I'll get stuck with the Riel. I have plenty of US$ already.
Also can anyone recommend which side of the border I would get a better exchange rate?
Probably better rate in Cambodia but I wouldn't change it directly at the border. I don't know where you enter Cambodia but in the border towns on Cambodian side the Baht is commonly accepted, mostly quoted and best value. So if you intend to stay some time near the border....
As for the 3000 B.: Doesn't matter either way. You'll have plenty of time to spend that on small items (mototrips, cigarettes, water etc.). All bigger things are quoted in dollars so that would be useful as well. Just see what gives you the best rate.