We normally do split stays since because our
DVC points only take us so far

and we must save points for next year! Being near the MK is great, but we are forever going to Epcot at night for dinner and strolling.
Pros: Closer locations to some parks-i.e. MK resorts-great for MK access, same with Epcot resorts-close to Epcot & DHS. Less bus rides the better for us.
Get to experience more than 1 resort and pool areas
If you end up not liking your pick-it will change
Note: We rent a car, which is more convenient to move resorts. Items don't need to be fully packed and laundry in baskets. Not everyone has this option
Cons: Packing up and moving takes time, but if you plan it right and take advantage of FP+, you don't have to worry about missing out on rope drop or high demand rides (Pro)
Often at BLT the rooms aren't exactly ready at 4 PM! This has happened to us a few times unfortunately and if you have little ones that need naps (or adults who needs naps: see my mother) or wash up before dinner it is a drag
If you love your resort and have to change it's a bummer!
The beer gets warm
You need to learn the layout of another resort
They don't work for everybody, but we enjoy the variety.