Good question
PPO Vs MACD
PPO oftentimes will look (almost) exactly the same as MACD, but the PPO is better for higher timeframe charts like the Daily, Weekly and Monthly as the larger charts have bigger variances in price when viewing years of price history.
So the larger the timeframe and differences in price movement on the chart you are viewing, the more useful the PPO will be vs. using MACD.
Both tools are Momentum indicators but:
- MACD reports the absolute difference between the EMA's
- PPO reports the difference as a percentage
PPO also works better than the MACD for gauging trends on highly volatile currency pairs due to the large movements in price.
Hope this clears things up
PS: Here's a small document which also notes the differences between MACD vs PPO vs DPO indicators (3rd page).
