I am a member of a ROCOR parish. I would say some of the differences between a ROCOR church and all the others I've visited are:
No pews
No organs (I've only see a few organs in other churches, though)
Women in skirts/ dresses with scarves; men w/ long sleeves (usually)
Slavonic chanting, of course, in four-part harmony
You must go to confession before each reception of Communion
All-Night Vigil instead of vespers (only lasts 2 hours, not all night!)
Converts usually received by baptism, not just chrismation
"Tea" instead of "Coffee hour"
Bearded and pony-tailed clergy
Deacons are very prominent in the Liturgy
little breads (prosphora) bought by the people and sent up to the altar, with prayers
The priest's phelon (vestment) has a high back
Different hat for the clergy (more conical, less stove-pipelike)
Always on the Old Calendar
People kiss the chalice after receiving Communion
But as has been noted, Orthodox is Orthodox.