Intertrader is the first spread betting system I've tried. UI and betting system work reasonably well, although sometimes the internal graphs may stop responding (it may be due to the Flash wrapper) both on Chrome and Firefox. The platform suffers in high volatility markets, where it becomes risky to do capping due to small delays in the execution of orders. Funding and withdrawing work well and the rebate system is also good enough in giving back some of the money you will inevitably loose while trading. Support seems active in seeking a contact with customers, although I couldn't test it in critical situations. Also, when I wanted to short a specific company I was told that wasn't possible due to insufficient customers betting on that ticker, which was both confusing as an answer and disappointing as a service.