I upgraded my 98 Subaru Legacy to a 01 Ody, seat comfort was a major reason. I am not tall, 5'10", but I found the Subaru seats to be really low to the floor, too stiff, and terribly uncomfortable after driving only a short while. The Ody seats are much better (but not great) mainly because the seat level is much higher off of the floor. I'm going to give them the Chuck Chainsaw Treatment or get the seat covers that Skybolt has suggested (any pics yet?) and see if that helps even more.
I can't comment on the Legacy but I recently took a 2500 mile round trip in my Odyssey. I found the seats to be more than adquate and never got seriously out of joint. One thing I found I appreciated on my '01 LX is the manual seat height adjustment. I'm 6'2 with rather long legs and I like adjusting the front of the seat upward so that the bottom cushion remains in greater contact with my thighs. It helped a lot for me!
I exchanged my '97 Subaru Impreza Outback for a '01 Ody Ex. I found the seats to be much more comfortable in the Odyssey on a long trip. The Ody's seats aren't the greatest but I found them to be superior to the Impreza. I don't know if this is any help but I thought I'd throw in my opinion.
My family spend a lot of time in the Odyssey.I've never been in a Subaru, buy my guess is it's similar to any sedan. The Odyssey is much more comfortable than a car/wagon because of more headroom, larger seats, and lots of legroom. Plus sitting up higher is more comfortable than having your knees up against the seat/dashboard. More room = more comfort.
I have a 99 Odyssey and I just bought a Subaru Outback Bean edition. I find the seats comperable as far as comfort is concerned, but they are different in how they are comfortable. The Odyssey has nice supportive broad bolsters, while the Subaru has more bolstered sides on both the sides of the back support and leg support with flat sections in between. Either are very comfortable on longe drives.
The only thing that would make the Odyssey slightly more comfortable would be a dead pedal. A quick copycat modification like Chuck did and would solve that problem.