Released in mid 2010, MetaTrader 5 is the latest version of the market-leading MetaTrader trading software.
Like MetaTrader 4, MetaTrader 5 allows users to access the Forex market through a broker, but also provides additional access to CFDs, stocks and futures.
This also means it is a more valuable asset for brokers, as it allows them to reach a wider customer base — this has resulted in a noticeable increase in the number of brokers owning MetaTrader 5, sometimes replacing MT4 entirely.
MT5 comes with a new writing language, MQL5 which is more efficient than MQL4. Although the interface is similar to the previous MT4 platform, MetaTrader 5 has more advanced graphical tools, including 12 more timeframes and more built-in technical indicators.
The MT5 also allows the use of an unlimited amount of charts, shows Depth of Market and has a built-in Economic Calendar. It also has more pending orders than MetaTrader 4 and has a built-in chat system.
The answer to this question depends on what you want from your platform and your commercial experience.
If you want to trade other CFDs as well as Forex, but want to be an independent customer, then the MT5 platform is a good choice. If you just want to trade forex on a simpler platform then it is a good idea to start with MetaTrader 4.
If you already have some experience with MetaTrader 4 and are thinking about changing, it really depends on your reasons. The only significant reason to switch platforms is if you want to trade in other markets.
The significant reason not to change is that programs written for MT4 will not work in MetaTrader 5, you will lose all your EAs, indicators and automated scripts in the transition.
The question is how much longer will MetaTrader 4 be used by great brokers. It is unquestionably the industry standard today and recent updates to the MQL4 language have made creating auto trading scripts almost as easy and efficient as MQL5.
That said, more brokers are always offering MetaTrader 5 and some have opted to only have MT5 in their tools.
MetaTrader 5 will eventually overtake MT4 as the industry standard. The fact that MetaTrader 5 is more complete, supports trading in all financial markets, and allows advanced testing makes it very attractive to both brokers and users.
Allowing risk coverage for non-US users was the removal of a major obstacle to joining MT5.
The only problem that remains is the lack of backwards compatibility with robots. MT4 and EAs — and this is a problem that will never go away.
If you use MetaTrader 4 and it meets your trading needs, stick with it as it will remain the gold standard for a while — unless you want to trade in other financial markets. If you're new to the market, it's worth considering going straight to MetaTrader 5.