I have used TradeStation 7 with automatic execution in conjunction with a TradeStation Securities account.
It worked more or less flawlessly, split second fills upon generation of a strategy order.
You cannot use TS to execute IB orders, unless you use something like Tradebolt or Trade Robot as a 3rd party add on application. I dont know anything about these programs, but have read of stability issues on the tradestation world forums.
As far as "is it profitable" goes then that depends entirely on the strategy or indicators upon which you let TradeStation execute your orders...