I've used both CQG and eSignal for many years. Though eSignal has primarily been a back-up, I spent sometime comparing the two in real-time last year. Now in the past, I believe CQG provided a superior product in all areas, but based upon my current observations, I find that, depending upon the area in consideration, this is no longer the case.
Take, for instance, charting. CQG's software is extremely slick, stable, and versatile. Nothing I have used is comparable, though most of the competition's software is developing rapidly and appears to be more than adequate.
Data comparisons, on the other hand, have seen the greatest change. At one time, CQG's data transmission stood well above other vendors but, within the last year, I've found eSignal to be comparable to CQG in reliability and speed, as far as the US markets are concerned.
Finally, concerning customer service, I tend to agree with previous comments regarding account handling, though I have nothing but praise for CQG's technical support. It's been a long standing tradition at CQG to project an image of elitism, not only through product presentation but in regard to their clientele. "Retail" has long had a negative ring on the lips of their account representatives and as such you will often get the impression that your interests matter not at all to them. That line has grown a bit old.
Considering that most of CQG's competitors now provide what I consider sufficient tools and data reliability to trade effectively, I can find few reasons for the majority of retail traders to use CQG, unless CQG provides some particular need.