To give you some background -
TASC only surveys subscribers for their Readers Choice polls. Thus, the poll reflects a very specialized group of people. TradeStation(TS) has been around for a long time. Other package less so. Therefore, there are more TS users and more TASC voters for TS.
About 5 years back the Cruz brothers, who control TradeStation, made a business decision to stop selling their product and only lease it. I don't know whether they were getting tired of the pirates stealing their software or that the Internet bubble burst and the sales of TS fell dramatically, or both. Concurrent with the lease-only decision was the dual fee structure - that is get TS for half price if you also trade thru TS Securities.
They have steadily improved TS and it continues to gain in power. However, when they made the change from sales to lease they also forced you to use their data. Their data is not cheap. Further, if you wanted to use non-market data such as the rainfall in Kansas as a driver in a wheat commodities system you could not. Some clever users have come up with ways around this but it is a nuisance. I understand that a planned future version will restore the use of "outside data".
Anyway, TS just announced "free" use of their software if you have enough activity in your account or maintain a $1M or greater balance. TS stated they wanted to target the trading professional. Your guess is as good as mine as to what that means. However, people consistently meeting the free software trading minimums probably fall into that category. What percentage of all customers will meet the "free" criteria is a guess. Commissions paid by traders have dropped dramatically. TS commissions are relatively competitive although their margin rates are not.
I know a number of traders that use TS, some with TS accounts, and some who pay the $200/mo plus data fees and trade elsewhere. They love TS. They have also used it for years. I own a copy of TS2000 and did not go to the leased model. I now use another package to develop my EOD systems. When TS brings back outside data I'll consider using it again.
Jack