Hello, have the skywatcher 300P (12 inch) collapisble dob.
I really like it. The shorter tube length does make moving it by hand easier than a solid tube.
I move mine in two pieces, and I custom built the base so I can't tell you how big and heavy the base is.
IIRC, the tube weighs 50 lbs, and is 38 inches tall???
I can carry this tube about 100-200 feet before needing a break (back or front yard). Over that and I use a cart, taking it to a local park.
As Diomedes says 50 lbs doesn't sound like a lot if it is a barbell, but carrying a bulky thing, in the dark when you are tired,
over rough and dewy ground (where did that gopher hole come from). Is right at the limit of my patience.
As someone else asked about stairs. I have three steps up to my house and I have to open the door at night while carrying the tube
I can carry an 8 inch dob in one piece much farther (not a mile).
Another thing to consider is thermal issues. The skywatcher has no fan. It takes 60-90 minutes for the mirror to cool 20 degrees.
You can add a fan your self if you are into tinkering. Medium and high power images are mush until the mirror cools.
The collapsible design holds collimation during the session, but I find I have to collimate both the secondary and the primary each
time I use it. I replaced the secondary screws with hex cap bolts I can finger turn for quick adjustment. And the primary is a large adjustment compared to the small tweak I have to give my solid tube dob.
I am not trying to poo-poo the 12, just go into it with your eyes open.