There is only one real advantage to being a ltd co which is the safety afforded to you personally if you (your company) goes into debt .
That's why your comment on your friend is confusing,or,rather, contradictory...
You say they had a company and "they went bankrupt". Why would they go bankrupt if they had a limited liability company? Why did it cost them a huge amount of money ?
If they had a company and it went bankrupt then in the normal course of events it should not have impinged on their personal assets. -that's why people set up ltd liability companies.
Most accountants will advise the ltd liability route if it is a trading company that involves the buying and selling of goods -most especially if you are selling on credit, and/or if you have high running costs (rent,staff etc). There is always the risk that the company will fail and incur debts.
But if your business involves no great running costs , has little risk element (debtors and creditors) and is basically a one-person business with no big turnover then there is little reason to have a company . Companies do mean annual accounts and other hassle.
You really have to work ouit the pros and cons - and -am being blunt here - read up about it.