The overall odds of the various prize categories in Mega and PB are pretty close, but he amounts of the prizes vary as you noted. For example should one get a 4-0 ticket in PB, it only pays $100, but if you were able to get the red PB with those 4 numbers, it pays $50,000!! In Mega if you get a 4-0 ticket it pays $500 and if you get the Mega Ball with those 4 numbers, it pays $10,000. This is 2 of the biggest differences in the two games.
Regarding lower prizes which are hard to win, 2 WBs + the PB or Mega ball or 3-0 prize, in PB these 2 prizes pay only $7.
In Mega each of these prizes pays $10. Then for getting only the PB or the Mega ball, Powerball pays $4, but Mega ball only pays $2. In PB getting 1 WB + the PB is still only $4. But since Mega only gives you $2 for a single Mega ball, if you get 1 WB + Mega ball, they pay $4. Finally another big difference in these games is the multiplier. The multiplier will always be at least a 2x, But Powerball can give you a 2x, 3x, 4x, 5x, or 10x. The 10x only is used until the jackpot amount reaches $150 million. Mega only uses 2x, 3x, 4x, 5x. Mega allows one to win $5 million if the multiplier is 5x, but Powerball will only pay up to $2 million no matter what the multiplier is.