Hi Joe,
Welcome to IceInSpace
You have selected two great scopes to pick from.
I own a Skywatcher Flex DOB 12"GoTo and am very happy with it.
However, I believe the Orion to be slightly better quality, but the SW Flex DOB (collapsible) is significantly quicker and easier to set up each time then the removable Truss system.
Tough decision.
I think if you intend to move to GoTo eventually, it is better to have the purpose built unit than to "upgrade" a manual unit later. (Just my opinion).
The eyepieces that come with both of these are good standard eyepieces and should keep you happy for a while.
Other accessories could include a light shroud to cover the open tube; a collimator; an adjustable height observing seat; and a red LED headlight or torch.
My DOB came with a straight through finder scope, I bought a right angle finder ASAP and a Red Dot finder also to make quick and easy changes to object selection. (The SW DOB can be used as a standard push to for easy find objects without disturbing the alignment).