6.5 lbs seems like a tank of a tent to me. I like my tarptent : ) I keep the insert in it, so it's a double walled tent for all practical purposes. Fast pitch. 2.5 lbs. luxurious for 1. I liked the eureka, and considered hoop tents, but no complaints about the double rainbow.
Weight on any one item isn't a huge deal though. at the end of the day, the 6.5 lb cheap tent is just as good if it keeps you dry, and if you took that extra money and put it towards a nicer pad, better pillow, and better sleeping bag, you'll probably get a better night sleep and wind up feeling much better about pulling that extra 2.5 lbs. : P idc as long as I'm riding.