Interesting discussion.
First, what do you consider large? 14", 16", 20", 25", bigger?
I got into the hobby a year ago. I have an 8" Orion XT8i Intelliscope. For me this was as big as I wanted to go. I could have had a 10" but I wanted the scope to be very convenient at a weight I could easily lift as a unit, so I went for the 8 and am glad I did. It lives on a cart in my garage. I can roll it out to the observing location in front of my house with ease.
Naturally I am already dreaming about a bigger scope.
12 to 16" SCTs look wonderful but are just too expensive.
If I stay with a Dob design, which is likely, it will probably be a 14" truss Dob as this is the tallest I can put on a cart and roll it out of my garage while vertical. Also I can reach the eyepiece on a 14 without a ladder. And if I want I can take a truss dob apart for transport. The Orion XXL14I or G are the target scope for the next upgrade some years down the road.
http://www.telescope.com/Telescopes/...CategoryId=398
If I went bigger than that I would want to have a permanent observatory. I don't see that ever happening, but that XX14i or XX14G are real possibilities.