Hi Ryounkin! Welcome to TL!
For eMinis, yes most of us here trade them and not stocks, but we love traders of all kinds
For differences...I've only traded ER and YM, and those two are the exact opposite of the spectrum from eachother. ER is very fast and very volatile and if played properly, the most profitable on a per tick basis (10 dollars per tick instead of 5 for YM). The YM really suits my personality as it's a laid back easy going contract to trade.
The NQ and ES I can't help with, unfortunately. I do know there are people here who have traded these two, so hopefully they can shed some light.
Hope that helps!
Chris