It depends on your needs and preferences. MT4 is the older version and more widely used, while MT5 is the newer one with some extra features. If you're a beginner or prefer simplicity, MT4 might be your go-to. It has a huge user base, lots of available indicators and expert advisors, and is compatible with most brokers. MT5, on the other hand, offers more advanced features, like additional order types and built-in economic calendar. So, if you're an experienced trader or need those extra bells and whistles, MT5 could be worth checking out. Ultimately, it boils down to your trading style and requirements. Give both a try if you can and see which one suits you best.