I have used these, I liked what they were offering as can use faster payments from a UK bank account.
However their service has been incredibly poor, I had trade a go through at the market price instead of the limit order I requested, I was unable to cancel pending trades as this could only be done by contacting them during business hours mon-fri 9-5. And finally they failed to credit one of my deposits forcing me to send screenshots and evidence. Still waiting for the deposit to be resolved. I will be closing my account with them soon after.