I have always been a 'DOME' person. Not only because, to me, they look like observatories, but also because of the severe winters we have here. The protection given by only allowing a slot to open is appealing.
BUT!!!
I was out doing a final measure on my set-up 2 days ago to find out the minimum size dome I will need to build. The Diameter of scope movement with my 12" on the EQ is 8'4". Then I hopped up on the ladder to measure the height I would need.
Whilst doing this height measurement I said to myself
"Now, when I am observing with the EP about here . . . hey, I don't observe with this set-up!" 
It was then that I realised that I don't need a Dome as I spend all my time sitting in my little cubby house controlling everything, which keeps me out of the weather anyway.
When I observe by eye I always use my Dob base! When the 12" is on the EQ it is for imaging.
I really have no need of a dome at all!!! As much as they look 'Observatoryish' I can happily
do without.
So . . . the new decision is to make a comfortable room for the 'Mission Control' centre, and just a removable (or slide off) cover for the Mount & Scope.
All this is about to happen.
In my voting above I had to tick
'I don't have an observatory but planning to build one' only because with my current set-up I have to bring the scope inside. Mount, pooters, cables etc all stay outside. So I'm sort of half and half at the moment.