They are really two different solutions.
Folder Redirection - We adopted this corporate wide on this premise - We in IT are responsible for making sure that our users do not need to be IT experts. It is our job to backup their data and give them a location that they can access across the campus if needs require it. By using folder redirection, we move the data, that also belongs to the company, where we can protect it with daily backups. The user is no longer required to backup key files as long as they use the my documents structure for their working files and the shared work folder for workgroup data. Remember, your non-IT customers have a job that they do best. Making them IT folks also is not necessarily in anyone's best interest. They hired us to make sure that even if someone in their department does click on that file attachment, it will do no harm. (I know - I too wish they wouldn't, but it is easier to design a better security config than upgrade the users.)
Roaming User allows a customer to go from set to set with their settings. If used with Folder Redirection, it can be managed, but the roaming has a high cost in maintenance as the roaming profile is easily damaged if logging out has issues (write back occurs at log out and is not journaled.) But, it also requires tight management of the profile policies and IE as the profile can become overly large if it is not finely tuned. Large profiles can increase log in time greatly, especially where bandwidth is 'challenged'.