I have been riding on tubulars (also called sew-ups) for approx. 25 years. In my early racing days (let's say younger years), I remember changing them in the fraction of the time it would take to replace the tube of a conventional tire, that is the advantage. The glue will usually keep a spare tubular in place to the the finish line. They are a pain to repair, yes, but I don't agree they go flat more often then tires.. Rims are also very light. You can find inexpensive and still very good used rims on eBay and a good new tubular can be found at around $20-25.