It really depends on personal preference and what you are putting in the truck bed. Both types of truck bed covers are practical for security and weather-proofing. The main difference is the functionality and how you use your truck bed.
If you usually don’t need to open the truck bed cover all the way, then a tri-fold tonneau will likely work for you. However, if you normally carry larger, bulkier items in the bed and need access to the entire bed often, a roll-up could be the better option for you.