I used to daytrade stocks, now I daytrade the ES. The setups I used for stocks do not work with the ES at all. My trading approach had to change drastically.
There are some real benefits to futures for sure, however there are some real dangers for those new to the game. I feel an especially dangerous trap to fall into is trying to use the same setups, etc that worked in stocks. That can often lead to quick disaster.
If you are currently using the ES as a leading indicator, I would suggest that before you switch from stocks, spend some additional focus time on how the ES moves and trades in certain situations, times of the day, etc. Try to develop an approach, then paper trade it either live or on a simulator. Maybe spend a small portion of the day just focusing only on the emini chart to see how it is trading, stuff like that. Just become intimate with it. See if you really like spending that much attention on one thing, or do you get bored and wish you were playing in lots of things. And what I think is the most important advice, once you switch, go small..1 contract only.
As discussed in this thread:
http://elitetrader.com/vb/showthread.php?s=&threadid=30805
the ES has some serious competion in it, you need to be very comfortable with it or you can get slammed.
I wish I would have done more of what I suggest above, because when I switched I was cocky and took a hit. And note - A hit in futures can be a real hit, your money management needs to change for it as well, and failure to do so is also a trap many fall into. Leverage kills!
All that said, once I took a few beatings and learned some lessons and became realistic about position sizing, I found that I am much more consistent with the ES than I was in stocks. I still take some beatings...last Friday being a good example, but ultimately my P/L is better and I like it much better. The learning never ends...
Hope it helps,
Dodger