CO is the only airline (US that is) that I've never ridden up front with - I had a string of horrible experiences several years ago and have refused to step foot on one of their planes ever since. When I last considered them I lived in CA, but all they fly from IAH to YYZ is ERJs... I will NOT spend 4 hours on a cigar tube. Now that I'm on the east coast, I hear I should give them another try...

I really think a lot of the experience depends on where you fly out of and where you fly to. People have mentioned widebody UA F - but that's not out of BOS. AA in BOS is mostly Not-So-Super-80's and even less super ERJs. DL is lots of CRJs or you go to Atlanta or CVG. B6 is half an airline at best (though a nice one.) UA is almost all 757's and 319's to their hubs. So as hard as it is to believe, to fly direct to the bulk of places I go, US is the best airline supplemented by UA....

Now that I've been told that better exists, do I want to sample them knowing that I'll still have to fly US for the bulk of my travels if I want to go non-stop??