I taught in Mooneys for a while at a Mooney dealer. It was cool getting to fly around in factory new 201s 231s and the 252. I took a 252 up to FL290 one time with the new owner. The 252 has pressurized mags and was certified to FL290 so we thought we would give it a try. We had a little hypoxia experience while up there.
I had briefed the student all about the importance of oxygen and given him the standard precautions about preflighting the oxygen system etc...While we were up there I looked back at the O2 fitting and saw the green flow indicator so I knew we were getting O2. But something occurred to me, what if the flow indicator was stuck on green. How could I be sure we were getting O2 flow? I figured I could pinch the hose just upstream of the flow indicator and when the green when to red, I'd know. When I did, the hose expanded and popped off the fitting
Now I was holding a piece of hose in my hand trying to put it back on the tiny fitting. The whole time I'm thinking, "30 seconds of useful consciousness." I looked over to the student to tell him what happened and then I noticed he had blue lips. His hose was kinked or something and he was just flying along with this big grin on his face.
I managed to put the hose back on the fitting and then straighten out his hose. We decided to descend. It was scary at the time but we laughed about it on the ground.
As far as flying the Mooney I can affirm what the others have said about landing flat. Just remember to be on speed. Too many people land 5 to 10 kts fast. You must be on speed to avoid bouncing. Also, starting the 201 can be a challenge. The engine can get vapor locked fairly easily. You really need to start it with the mixture out and slowly bring it in to fire it up. I backfired the engine one time while starting at the fuel island to taxi back to the ramp. When I shut down, smoke poured out from the cowling. I had somehow ignited the air filter and burned it out by the time I got back to the ramp. I wonder about all the ash and crap I sucked in to that engine. I don't think we ever told the owner.
One more thing. When you practice engine out, check out the difference in glide between the prop forward and pulled back. It is amazing how much better it will glide with the prop back.
Have fun and remember to put the gear down.