Quote from SteveH:
With IQFeed, can you run multiple 3rd Party apps at the same time plus write your own applications to use their datafeed without paying more than the standard real-time fees?
With eSignal, you can run multiple 3rd Party apps simultaneously sharing the data feed at the flat annual rate. If you want to write your own, then you pay a one-time fee ($200) and then a monthly fee ($20). It's an ActiveX plugin so you can easily use .Net if you like.
To put things in a real-world, small business perspective, the cheapest tick-based data feed is going to cost you $3 a day while eSignal is closer to $6 (based on a 240 day year). Most businesses which are non-internet, at-home based are looking at $100+ per day in overhead just to open up their doors.
[Caveats: TradeStation is a little cheaper than IQFeed but you have to trade through them]