I find the Motiv bag to be more maneuverable than the Storm bag actually. The wheels on the Motiv bag roll easier in my opinion and the bag has a natural rear tilt where the Rolling Thunder seemed to have a slight forward tilt if not neutral.
I used it for the first time last night, and there are some differences that will take some getting used to. The handle on the Motiv bag doesn't collapse as far down as the Rolling Thunder bag, perhaps by as much as 6 inches. This makes picking up the bottom half and putting in the trunk of a car a different motion, but nothing I can't get used to the change.
One issue I would have never guessed is the Motiv bag wheels are set back from the bottom of the bag a bit. Where the Rolling Thunder wheels are pretty much flush with the back of the bag, the Motiv wheels stick out maybe an inch or so. This causes the Motiv bag to more readily slide around(front to back) in your trunk. The Storm bag never had this issue as the entire back of the lower part of the bag came into direct contact with the floor of the trunk. With the Motiv wheels protruding out, the wheels and a single point of contact of the handle support allows for the bag to slide back and forth much easier when the car is in motion. This can be solved by setting the top half on the handles.
The other thing I noticed is the Rolling Thunder handle is a one hand operation to raise and lower the handle as the release is part of the hand grip. The Motiv bag has a button that has to be depressed lower down on the handle which makes it require both hands to operate.
I still like the quality build of the Motiv bag over what my last Rolling Thunder had though.