Just mentioning something that is probably obvious to most, that holding share just for the shareholder benefits alone is risky. This is a quote from HL "Shareholder perks are not reason alone for buying shares in a company. Over time, shares and any income they pay will rise and fall in value, so you could get back less than you invest. If you're not sure if an investment is right for you, please speak to a financial adviser."
In my case I lost about £30 immediately after I purchased the shares. After that it fluctuated quite a bit and currently I am about £34 down. As with all shares, I am taking a long term view on growth and dividends. At least currently we are seeing quite low share prices and hope is that things can only get better. Of course, if you take a lot of cruises with Carnival owned cruises companies then you could recover some of your potential losses quite quickly. Some people on this board have had more in benefits than initial outlay on the shares.