I've been with them about 3 years. I'm please with them. The customer service has been good when you have an issue.
In the recent incident with GO owners being shorted some of the divy, which E*Trade did along with a slew of other online brokerages, they actually corrected the difference (or nearly so). This gave me a renewed confidence in them because I was beginning my research on the other online brokerage sites mentioned above like A-trade.
On a side note, I like E*trade website and all the goodies it has (Market tracker). The other sites may have something similar so I can't speak in comparisons.