I rode tubulars for years. The rim/tire combination is lighter than almost anything you can get with clinchers even today and they do have the 'cool factor'. However, I switched over because every flat became a maintenance project.

Its not that easy to fix the tire itself with all of the ripping and sewing base tape gluing. Some people have probably gotten pretty good at it with practice. But it probably took me at least an hour for that part and I wasn't always succesful. Then you have to clean up the rim and re-glue the tire. Again some people might be fast but that probably took me about a half hour. Which put me at about 90 minutes per flat via 5-10 minutes for a clincher.