I cannot speak with a great deal of Mooney experience. I just purchased a Rocket and have put about 10 hours in it so far. What I can offer you is a Mooney Noobs initial impressions.
-The aircraft handles like a much larger airplane. It does not have a light sporty feel. This is something I actually really like about it and makes it a great IFR aircraft, though I do not intend to fly in LIFR since it is SE.
-I have not done stalls so far in the aircraft, however from what experience I do have you would have to really not be paying attention to get it into a stall. It takes effort to get her slowed down as the air frame is pretty clean even with gear and flaps out, I find myself using speed brakes even when fully dirty. This combined with a pretty low stall speed to begin with mean that you really would have to have your head up your butt to inadvertently get into a stall. Again, I cannot comment on stall characteristics as I have not done any yet ( I know, shame on me)... The flying has mostly been for acceptance and relocation. It is in paint now and when I fly it next I will be doing stalls so i can report back.
-You absolutely cannot be fast on landing. You WILL float and float and float
-You ABSOLUTELY cannot shove the nose forward to stop said float. You have to hold the nose up on landing and if you are worried about landing long you had better go around.
-The Rear seats are surprisingly roomy. I am 6'1" 240 lbs and Dare I say that the rear seats are more comfortable than the front.
-If you are Older/ out of shape or otherwise creaky, getting in and out might be a bit of a challenge... you climb up the wing and then down into the aircraft.
-these planes are fast (especially the rocket) It baffles me that mooney has everything but the experimental glass ships beat when it comes to speed/ efficiency. The more I look at other air-frames the more respect I have for what Mooney is. I believe a great deal of their performance is due to the tail design.
-useful load is obviously different for each aircraft... However as another poster stated, there is usually fuel that can be left behind. Be certain you are comparing apples to apples when you look at useful loads. Don't look at a 900 lb useful load aircraft and automatically assume it has a lower FF UL than an aircraft with a 1000 lb UL. It may hold less fuel/need less fuel to go the same distance. I looked at BO's when I was deciding what to buy and do not think the Bonanzas are in all cases better than the mooney when you really look at the numbers.
Final thought... I bought an aircraft to travel. I wanted to be able to go 190+ knots and do it efficiently... Mooney has the only Piston Singles that can do this unless you look at experimental.