I have been on Tubulars for years on all three of my bikes and I have been on all levels of tires, I have latex race tires on 2 sets of rims and butyl tubed tires on the other 2 sets (1 spare set) and when I am going out to eat some miles and I want to be 100% sure that I am going to make it home without problems (2oz Stans per tire) these are the tires I use, from memory 3 sets of Corsa Elites, many hours and miles, 2 punctures (found out when I got home), 0 flats, No Drama.. I am not going to address the leak down issue thats just silly, you should always air up tires before you ride..
I used to use the Evo Corsa CX III tires (25mm). I loved the ride quality, but the latex tubes bled air incredibly fast, and the replaceable valve stems were fragile and tended to leak. Bottom line was that I just didn't trust them to hold air for any length of time (they'd lose easily 10 lbs over a 4 hour ride). I switched to Tufo Elite Ride (25mm) and appreciated their toughness, but not the relatively harsh ride, so decided to give Vittoria another try when this model, which has butyl tubes and a non-removable stem came out (valve cores are removable). I put these (25mm) on 2 weeks before Boise 70.3, loaded each with a small bottle of Stan's No Tubes sealant, rode them for around 150 miles, then raced them 56 miles. No flats despite riding some sketchy roads, and that Vittoria feel is back - so smooth it makes you feel like your tires are under-inflated. These are the Vittoria tires I've been waiting for. Tough, light enough, reliable, and great ride quality. BTW I removed the Vittoria valve cores and used Continental 30mm valve extenders to go through 50mm carbon rims. The Vittoria valve cores fit perfectly in the Conti extenders and I have no leaks - tire pressure stays high for days.