Millenium for me. Most comfortable stand I've used. Regularly do full day sits (before sunrise until dark) in November here in Michigan. Couldn't pull that off in one of my other stands.
I've owned/used all kinds of stands over the years, and have come to the conclusion that I need some sort of sling seat/armrest. It allows me to wedge myself in place and fall asleep (impossible for me to sit on stand for 10+ hours without nodding off occasionally) without worrying about sliding off the seat. The design of the Millenium allows me this comfort, yet doesn't cause any problems with bow limb clearance that some other designs have.