I have Footmasters on my Jet 3520B lathe and it is easy enough to move around, all 300kg+ of it with assorted junk on some shelves, and rolling over a carpet.
Mine are the cheaper variety which require a spanner to raise and lower, rather than the built-in lever on the more expensive ones.
As my lathe is heavy, I leave it pretty much permanently on the castors so that I can move it around without any trouble. It does wobble a bit with unbalanced workpieces but I can always lower it if I need to, and it's fine with balanced pieces.
On a lighter lathe like the Jet 1440, I think you'd need to lower the lathe to the floor a little more frequently than I do and, if I was going down that route, I'd make sure I get the ones with built-in levers.
There is a parallelogram (?) lift design which raises and lowers a lathe off and onto the castors far more quickly and I think I'd be inclined to go down that route with some ordinary decent quality castors. I'll see if I can find the design.
Duncan