Pulling the bag using the RetaStrap is similar to pulling it by hand. Same angle, same point of contact, same strength and speed. Which means same maneuverability. The bag follows you and turns when you turn (up to 90 degrees).
Most of the times when your bag tips over is when you try to put it in the upright position and trying to balance it. With the RetraStrap, you don't need to park the bag each time you stop to take a break or when you need both hands.
Tip: Whether pulling the bag by hand or using the RetraStrap, always pack your heavy items as close as possible to the bottom of the bag above the wheels and the lighter items on top. This weight distribution is best for balancing the bag when in the parked position, and it feels lighter when pulled.
Going up or down  the electric escalator while using the RetraStrap may require you to park the bag in the upright position. The RetraStrap makes it safer by keeping the bag from falling down on other people below you.
You can easily step down a curb without reaching out for your bag and the bag does not tip over. Always make sure you approach the curb perpendicularly with both wheels at the same time to keep it balanced. Going up the curb may require you to pull by hand depending on the weight of the bag and the height of the curb.
You do need to carry the bag up or down regular stairs but you don't have to remove the RetraStrap.
Always pay attention to other people and objects around you when walking, it is so easy to forget that you have a bag behind.