Mr Munoz,
My wife (business partner) and I left United earlier this year after 25 years of loyalty.
While we would echo the comments made on many of the previous posts, our decision to leave was based on United's horrid reliability. Twice in one week we were left stranded at one of your hubs and forced to rent a car and drive all night to get home. The only option offered by United was to wait 24 hours for a seat on the same flight the next day. Biz flyers need to get where they are going when they need to get there. Not a day or two later because every seat on every other flight is sold out. After flying Delta for 6 months now, its clear their employees do what ever it takes to accommodate IRROPS. We fly enough to know that Delta will eventually screw us over too but at least I don't have visceral fear of being screwed over when we walk into the airport.