cTrader is developed by Spotware and is the preferred platform for scalpers and active discretionary traders. It shows full depth-of-market (Level II order book) on every pair, supports one-click trading with precise volume controls, and has a much more modern UI than MT4/MT5. Its scripting language, cAlgo/C#, is far more capable than MQL4.
cTrader is available from a smaller set of brokers — notably Pepperstone, IC Markets, Axi, and FP Markets — but those are precisely the ECN/raw-spread brokers that scalpers gravitate to. If tight execution and depth visibility matter more than EA availability, cTrader is usually the right choice over MT4.