Where to put money instead of 401k?

I will be starting my job in August and I was just looking at the firm's 401k plan. They match 25% of up to the first 6 % of my eligible compensation saved. Basically, for every 4 dollars I save they firm adds $1.

Now, I am thinking about saving and investing some money. I believe that I will be able to save about $1400 per month. Out of this amount, I want to put $400 into my emergency funds account.

What do you guys think how should I save money for the long term and also where and how should I invest some of this money.

401k is a safe and easy way to save money, however, I am not from the US so if I move back home (which I plan to do in 10-15 years) I will need to pay penalty fees on my 401k account.

Any ideas?

Thanks