We gate check a wheelchair all the time, so I feel like the queen of gate checking.
From what I have been told from various airlines we've traveled on, gate checked items are placed on the plane last and are the first off. In all our years of travel, we have had DD's wheelchair damaged once. An antitipper bent. Those are little bars at the back of the wheelchair and it would take a lot to bend them since they are meant to take the full weight of the wheelchair and prevent it from tipping backwards.
I have also read posts from people whose gate checked strollers got bent. To prevent that, fold your own stroller and make sure it is secured shut. Make sure that canopy or anything else that is loose is also secured. Some people have posted that they put the strollers in bags even when they gate check.
Ask for a gate check tag when you first check in. They may give you one then or tell you to get it from the gate agent. The gate check tags usually have several choices of where you would like to have your stroller delivered (gate or baggage at final destination or connecting flight.) Make sure the appropriate one is checked. If you have enough time between flights, you can have the stroller delivered to the gate when you land for your connecting flight. We are usually the last people off our flights and often see strollers obediantly waiting at the gate for people who are already gone.