For 1, DNS is one possibility. What are your DNS settings? And YES, Roaming Profiles can cause long delays.
For 2, In theory, no.
For 3, Folder redirection is a registry setting that is defined (typically) through Group Policy. All it does is change the default locations of Profile folders to a share on the server, including (depending on which you choose to redirect) the Desktop, Application Data, Start Menu, and My Documents. Typically, I recommend redirecting My Documents and the Desktop.
When your users log on, the My Documents folder automatically goes to the network and displays the contents of the network folder defined to be "My Documents"
In roaming profiles, when you log on, ALL your profile data (except for the Local Settings folder and any others you specifically exclude manually) are copied from the server to the workstation. From there you work off your profile normally. Then when you log out, the data is copied back to the network. While the 2003 version of roaming profiles has improved some, it is still a less than ideal solution in my opinion because, for example, if your user downloads a large ISO file (lets say an ISO of a linux distribution) and saves it to their desktop, that file must now be copied back to the network, wasting bandwidth and time as the the logout won't finish until the copy does. In this same scenario, if folder redirection were used, the file would have been downloaded to the server and would remain there, never being automatically transferred back and forth with the client(s).
(#3 was actually cut and paste from a recent question on another site that I answered - it was very similar to yours, at least with the pros and cons).