I don't use them but If they don't offer a free trial, (which I don't think they do) I wouldn’t touch them. I know they will give you excuses of how good their service is and all that but without a trial you are throwing your money away.
I use a similar signal service tradingedge.co.uk and they were free for 4 months at the beginning plus they offered me a 14 day free trial no questions asked before I subscribed, I didn't even have to give them any credit card details for the free trial.
I hope that helps.