When there is a lot of volatility ( market goes down and it goes down fast ) some Es options lack a bid and and ask. You can still make a market, but you will get royally screwed if you still have to get out from your position.
There were good answers above.
If you are willing to take a bit more risk the return you make with ES options will dwarf SPY options return, but you have to be on top of your game.
ES options are as hot as fire. They can and will destroy your account soon if you don't understand well how to use leverage/margin.
I started placing option spreads on ES options after 5 years of trading and I still had to go trough some pretty humbling experiences ( lost almost the entire year gains ). It would have been a smaller loss with SPY options so be very careful.
You can start with a 15% margin on your account and move up your margin as you get better just don't be in a hurry.
It is definitely worth to experiment and try both. To better understand the difference you can place the same position using both on a simulated account.
Good Luck.
There were good answers above.
If you are willing to take a bit more risk the return you make with ES options will dwarf SPY options return, but you have to be on top of your game.
ES options are as hot as fire. They can and will destroy your account soon if you don't understand well how to use leverage/margin.
I started placing option spreads on ES options after 5 years of trading and I still had to go trough some pretty humbling experiences ( lost almost the entire year gains ). It would have been a smaller loss with SPY options so be very careful.
You can start with a 15% margin on your account and move up your margin as you get better just don't be in a hurry.
It is definitely worth to experiment and try both. To better understand the difference you can place the same position using both on a simulated account.
Good Luck.