Index futures, yes, I do. Have since late 2006 when transitioning from equities.
Currently 90+% of my volume is ES, 5-7% 10YR & 6E, remainder smaller swing positions in ags/metals. Never use NQ/YM. Intra-session only on ES/10YR.
Last year was a slower year for me, but 2013 has heavily picked up. March and April set two consecutive PnL career records for me. ES is trading quite well. Very good fill rates/quality this yr minus a few pockets early-mid April. I monitor the top 20 CME products rather closely, you couldn't pay me to remove ES as my main repertoire.
Any specifics you would like addressed?