One of the prime questions always disturbs me that How I can invest Bitcoin? How can I trust any of the exchange if I invest in them?
There are many ways to invest in Bitcoin. You can buy and hold it or buy and trade it, depending on your appetite. Regarding trusting an exchange site, it depends on your research if what site do you think is good. You should be aware that an exchange site could be good today but gone tomorrow so as everyone says when it comes to invest "only invest what you can afford to lose".