The most difficult thing about rod building is the cork work (followed by a professional looking finish). It requires the proper equipment and something of an artistic touch or feel. I've seen alot of basement rods that were soundly constructed but had some bizzarre looking handles.
In my opinion, while the preformed handles do look like they are easier, they often get tricky. The 1st rod I built I put individual corks on and shaped it by hand - a pleasing, vaguely familiar repetative action, but not really that effective. The next 2 or 3 grips were pre-formed, I didn't like the quality of the cork and it was difficult to get a satisfactory fit. even using the recommended tapered reamer (a section of rod blank coated in glue and rolled in quite rough grit) which I found was very effective on individual corks. Eventually I made my own rod lathe based on a drill and a custom designed roller assembly. If I get really motivated I'll try to put some pictures up here so you can see. For my money you cannot beat the individual corks glued to the blank and turned on a lathe.
As for glue, I've always used 5 minute epoxy and never had problems. For those who don't have access to a lathe there is another option. You can take your glued handle assembly to a custom rod builder and have him turn it to your specs - a very effective and relatively cheap option. To find one of these guys check with your local flyshop - I know Michael and Young has at least a couple of custom builders.
Tight lines - tyler.
Still Living Large!