Bitcoin code is proven to be safe, the transaction between bitcoins are also safe because it is confirmed by lots of computers. Concerning your bitcoin investment, it has nothing to do with bitcoin codes since it is your decision and other people who exploit other people to gain money by scamming them of their bitcoin.
Agree and it is also the basis for other alt coins. As an addition to safety, I may recommend to really backup your wallet if it is save on your hard disk as based on my experience,when hard disk fails or crash you will lost your wallets.Save the wallet.dat file in other media and put it in a safe place.
i'd agree with backing up wallet in another place for second backup even though it could increase the chance to be copied by another person but for the sake of your money safety,the risk above doesn't matter,really