I think it depends on the type of trading you are doing. If it's day trading and your trading some size it helps to have the daily squwark on. Often times the market moves and the squwark gives an explanation for it, which can confirm your own technical analysis.
I look upon them as the eyes and ears of fundemental information, in addition to one's own research.
Announcements of Sales of Bond auctions, or a particular large Company or institutions in trouble providing an explanation of a massive sell off or surge in price. They often announce details and figures that Bloomberg or CNBC don't due to their U.S centred broadcasting, i.e a lot of european news.
I believe the reall costs in trading from are the Round Trips. If you trade from home via an Acrade that should bring it down somewhat.
Hopes that helps.
First Call are quite good, and only £150.00 pm in one month the squwark should pay for it's self.