I'm a lightweight (as in 120ish light), and I love riding tubs. I have 2 tub wheelsets in addition to 2 clincher sets.
Because I'm a lightweight, I can get away with using tape instead of glue. With using tape, changing and taping on new tires is a cinch!!!
Climbing on a set of light tubular, or sprinting, feel so much better than on clinchers. Tubs just feel very snappy and you put down the power.
people in here have said you can use sealant on tubs, but I want to clarify that while sealants do work well on LATEX inner tubes, they don't work as well on BUTYL tubes. So keep this in mind when you do buy tubular tires. I have a Vittoria Pave tub tire that I've twice gotten a small puncture and twice it sealed with sealant, and the tire is still holding air and now it has worn down and squaring off the middle pretty much, so about time to replace it, which for me will just man ripping it out and putting a new tape. It's actually very therapeutic to tape on new tub!