MT4 is a trading platform which is most popular by the traders who are particularly newcomers. In my trading career, as a newcomer from my first day of trading I have been using MT4 broker that is really comfortable to me when trading practically.
It is very difficult to find a best broker from all, because there are almost thousands brokers in online Forex trading and most of them are found to be scams. You can choose a regulated trading broker which guarantee their clients finds.
if you trade in US with the regulated broker you will not get higher leverage. To get higher leverage say 200X you will need to trade with an unregulated broker or an offshore entity of the regulated broker. all this can be helpful in earning.
I use a broker that regulated on ASIC, this is regulation Australian based, and also company regulated on FCA, which this is regulation UK based, and the company also registered in Cysec, as I know this regulation in Seychelles, and based my experience this is good and trusted broker.
In this trading place choosing a broker is very much difficult, because there are almost thousands online broker in this retail market and most of them are found to be scams. We can choose the broker which is more appropriate to the concept of trading that will be used; if you love scalping should choose the broker that allows trading concept such as this.