Looking for Drone Suggestions

Hey All.

I sponsor a Drone Club at my local middle school where I teach 6th - 8th graders how to fly drones for aerial video. I use large indoor areas like the gym and cafeteria to start them out where they don't have to fight the wind. You have to understand that kids are just developing their fine motor skills so they often hit the walls and many crashes happen.

I have been using the Syma X11 because they were cheap but here is were they are failing to meet my needs. The X11 is not really that stable. It can take crashes but it often gets out of wack and then takes to much trim to correct it into a stable hover. Many times the motors fail and it requires fine soldering of which I stink. The control boards fail too often.

I need a drone that is a good learner drone. Something that is very stable and durable, that can take a beating. It must have prop guards to protect the walls. I would like it to have easy exchangeable parts like the Dromida's motors have electric connectors and easy to change. Low cost would be great but if the parts are easy to replace and easy to get I will go with the higher cost.

I have even considered some of the 250mm racing drone platforms. I am not so concerned with costs if the investment is a good one. The X11's were costing $25 each but only last me about 4 sessions with the kids.

Any help or suggestions will be greatly appreciated.