Quote from rallymode:
Yep, love them too. Margin benefits are incredible, low liquidity though so you must be good at legging in if you want nice fills on multi leg positions.
Quick example on ES vs SPX options. The strike below isn't FOTM, but its illustrative regardless. SEP ES currently has about 10 pts of premium; I'm ignoring that for the examples below. Margin requirements are from IB.
ES ~ 1237
ES JUL 1200 Put 18 bid 18.75 ask
Margin to sell naked the 1200P: $2200
-1200/+1190 spread 1.5 x 3.0
Margin to sell the 1200/1190: $930
SPX ~ 1227
JUL 1200 Put 18.5 bid 20.10 ask
Margin to sell 1200P naked: $18758
-1200/+1190 spread 0.9 x 3.9
Margin to sell 1200/1190: $1858
ES is $50/pt, versus SPX $100/pt. So doubling the ES spread margin makes it similar to SPX.
On ES, the market you see on your screen *is* the market. So while the ES spread is much tighter, you won't be able to play around in between the spread. If you put your order inside the spread, *your* order becomes the new bid or ask. With ES, you give up a bit in that regard. However, you also don't have the huge execution risk you encounter on SPX. I.e. if the market hits your price...you're filled. No calling the order desk and hoping they can get their buddy in the pit to work your order. No haggling over the midpoint. If you like the number on your screen, make the trade and you're done.
SPX certainly has a ton more volume, not that the extra volume is reflected in the wideass spread. ES usually has 200 to 400 contracts listed on each side. I don't trade size on ES, so I can't comment on how easy the fills are for orders over the size listed. SPX you can trade as big as you want. Same is true for SP options, but then you're back in a pit same as SPX.