Tubes or not...

[Dumpster Juice]

I currently run tubes in my tires. I have been thinking of going tubeless, but after talking with friends who do they say they have to add air about every other day to keep them up. What are the Pros/Cons of tubeless? What happens when you have a flat on the trail and have to pump up the tire, can you without a air compresser? Why not just use some type of run flat tubes? Do yu have as many flats going tubeless?
I know some of these things have been covered in other post, but I cheat and look on line while at work and can't afford to go looking for fear of getting caught not working.  

[Blammo]

Pros
 - puncture resistance
 - snake bite resistance
 - can run lower tire pressure for smoother, faster ride
 - lighter in weight

Cons
  - harder to set up initially
  - messy when fixing a flat on the trail
  - might have to carry more tire sealant with you for long trips
  - can be more susceptible to slow leaks, but usually only for the first ride or so and depends on the tire
  - I suppose the could be more susceptible to freezing temperatures but you can add a little ammonia

I have run only tubeless for about 12 years now.  Only on road bikes do I run tubes and that may change some day.