The flexibility is a big one for me. Both in the shifts and in my wife being able to drive it if needed.
And I think an 8HP will always be faster than a manual. Both because of the number of gears and because of the option for torque multiplication. Even ignoring the torque multiplication, an 8HP with a 3.08 final drive will out pull a wide ratio T56 with a 3.71 final drive in every gear.
Add that an 8HP can save some money because you really don't want those 3.55+ gears that (generally) cost more due to popularity. I've seen people giving away pumpkins because they have "emissions era" gears in them. :D
I have debated that in my mind for years now. Still don't have answers either.
My gut says, it won't be the same and I will miss a manual depending on the usage. For shear drving enjoyment, I think a stick wins. But if I factor in the ability to swap drivers after 4 or 6 hours of driving so we can get 2 to 4 more hours in, faster and more consistent on the strip and not have to have neck breaking shifts on the road, the option of a transbrake and costs less, it get's harder to pick a winner.
I would add that one place a stick shines is in that shift violence can be adjust at a whim, so the 8HP is actually behind there. :)
And on a road course, not sure if an 8HP can do compression braking like a stick can. Probably, but not something I have looked into. Might just have to be something like a TC lock above 20 mph or something to get it. Not really sure, but probably a wash between the two options there as well.