Thoughts on US equity investing

Need help: I stay in india, but i am considering to invest in US stock market. If you've invested or are a regular investor in US equities, Please share any pros and cons that you feel that would help other investors.

Looking for inputs on topics such as,

1. Should one go for ETFs like MON100, etc or use apps like indmoney, vested etc, how's your experience here.
2. How do you manage or save taxes here?
3. Any currency conversion charges we have to face?
4. Other type of personal experience.