I have a Gibraltar "drum throne" that is very comfortable, and a fraction of the price of the concert design stool that I purchased before that. One of the big selling features of the Gibraltar, (other than the price) was that it's easy for me to transport, it folds up when I need it to etc. I also sit rather low for a bassist, with my seat about 22" off the ground, so this might not be an option for you.
Those "really REALLY good stools" that you see symphony bassists playing on? They are often owned by the orchestra, and they have a stage manager that sets them up for the section. If you plan on gigging/travelling with it, even on a not very regular basis, they SUCK to have to transport, and can take up as much space as your bass does in a vehicle.
Find a shop that has stools, bring your bass, sit on a bunch of them, and play a while. Then pack up your bass, and the stool, and see if you can make it back to the front door carrying both.
Just my $0.02