No feed is perfect but this gets close for me. That´s why I´ve been using eSignal Advanced Charts since it came out and before that Signal on Satellite (what an improvement the internet feed has been!)
For me the online library of efs write your own studies has proved invaluable in my trading. The range of Fibonacci tools in the Advanced GET part of the package I could not daytrade without. As far as support goes, genearlly they are responsive, though sometimes I have had to be persistant with them to get a response. A lot of problems are addressed on their forums. I have not used the DDE facility for some time(since 1998), though when I did use it it worked well to feed bespoke formulas via Excel into TS2000i. General feed uptime is excellent, and has improved recently. The last time I experienced a break was about a week ago, (and that was it for me as it was late in the day!) but before that I cannot remember a break in data. I was trading DAX futures at the time so this did not appear to affect US markets. Clearly this is not Bloomberg when it comes to support, but its not a Bloomberg price either.
Also, in the tech analysis department it leaves feeds like Zeh Bloomberg in the dust, so its a case of horses for courses and price points. Certain indicators and efs studies can bog down the front end application, and they could improve on this, but one has to be fair and say that in providing the ability to write and execute ones own code one must deal with the fact that one could then crash the system (i.e. Don´t drive a sports car if you don´t accept the fact that its a complex animal and a burst on the accelerator the wrong time can land you in the wrong place)!
I run a 2 screen setup, one with 9 charts and the other with only 2 charts and a quote screen on a variety of laptops. It does not get bogged down, but I heard there is a fairly well known trader on these boards who is using a bunch of 26inch screens and hundreds of charts. He has had to buy another eSignal feed to make them all work but he is also running lots of efs custom studies etc so I don´t know whether its the charts with the number of studies that slows the app down. One other advantage of the feed is that the application sits independent of the server. This mod was also instituted by the folks at Trade Station some years ago and is useful,as if the app crashes it does not crash the feed collector and restarting is reasonably quick. Years ago, it would take one Greek trader I know 30 mins to restart Comstock and TS everytime it crashed. If my eSignal crashes I am back and up in around 40 secs after the studies are loaded (one takes a very long time) otherwise it would be more like 10s.
One thing they could do better is to maintain more online daily historical data, even if they charged extra for it. For example, I can´t get access to the March DAX intraday stuff anymore for back testing. This is not great. They must be able to maintain this. After all it could be lucrative for them! Overall, this is an excellent datafeed and excellent value for money for the serious trader.