Agreed that CO is far superior to DL. Check out the DL forum to glipse the shenanigans that DL is pulling as they go into bankruptcy. I've been Plat at DL since current program inception. But for the coming year(s) it looks like the only way I'll be flying them is for free - got to use up 3M+ miles (though OTOH the way they're devaluing their miles and their program, it may take everything to get a single free trip from them.) Very unsavory goings-on at DL. Be careful before making a switch.