Yes, I did! I still get a funny feeling in my thumbs when I even sit on one of those tractors!
You had a diesel M? I'm jealous! Was it the one that started on gasoline? A farmer down the road from me has 3 of them, still uses them on a daily basis. He has a M, a M-TA, and a MD-TA. My uncle had a M-TA, he used it for years with a mounted corn picker, later traded it for a Farmall 656.
We had 2 TD-340's, one dozer, one loader, a UD-14 power unit that started on gas, ran on diesel. (MASSIVE 6 cylinder engine, pistons were the size of 1pound coffee cans!) a 460 backhoe, a Farmall H, 806, 826, an International 664, B-414 (hardest tractor in the world to keep brakes on, harder still when it has a loader on it), and a 3388. THAT tractor started out at 130HP, and I don't know how high I turned up the fuel on it, but it would totally outperform my brother's 4555 John Deere, and it was 155HP. Both tractors were 4-WD, with duals on the rear, and ballasted to about 18,000 pounds. My guess would put it in the 185-200 range.
We also had a 715 combine we did custom harvesting work with. I could set that thing up from memory, and had it tuned (air, sieves, concaves, etc.) within 10 minutes after starting into a corn or small grain field. I even set it up to do buckwheat one time. Strange grain, look like little, black pyramids.
If you had a gas start/diesel 6 cylinder power unit, that would have been a UD-16 or UD-18 unit. The UD-16 had the same pistons and sleeves as a TD-9, WD-9, ID-9, OD-9 etc....size of cooffee cans... probably a UD-18, same as TD-18 engine and a hell of a strong power unit...shoot, the UD-16 unit wasn't no slauch when it came to power for a sawmill or something.
NO BRAKES B-414..... Know exactly what you're talking about. We had the fore runner to that, a B-275. Hard as hell to steer, no brakes to help steer and to weak to pull a sick whore off the toilet. About all it ever did was pull a hay rake.
Yes we had several MD's over the years. My daddy had the first diesel tractor in the county. It was a 1947 Farmall MD....after that one, we usually just had diesels of that era on the farm...none of those larger later models you spoke of.
Combines...

...I only remember one. A pull type AC with about a foot cutter head and the old wood strips and canvas thing to carry the stems/seeds up into the combine and then it went into sacks. I was 7 or 8 when we were running it and I was supposed to be tying the sacks and shoving them off the back. I couldn't tie a good knot and about every third sack would open when it hit the ground. Daddy would pitch his fit and put me on the tractor. My legs weren't strong enough or long enough to work the clutch probably...and I couldn't steer the old MD for shit...so we'd make a couple of rounds that way and I'd get put back on the combine...we'd be switching back and forth all day...damn long days...

Then there was the ALLIS-CHALMERS round hay baler...the small kind, 50/75 pound bales. No live power on the MD's so you had to stop, take it out of gear, let it wrap and then clutch again, put it gear, go a few feet if you were in good stuff and do it all over again....whew, what a pain.
That was the late 40's, early 50's....when daddy got in trouble with the KKK for paying his black workers to much. They usually worked for a set wage but certain times of the year (spring plowing and fall haying) they worked on commission. They would some weeks make 3 to 5 times what people in the cotton mills were making. They worked their ass off night and day to do it but they earned every dime of it so daddy paid them. The KLAN called a few times to threaten daddy. He told some KKK member the last time they called what he paid the black fellows (2 brothers). He told the guy that

if any of the white KKK members would do the same for less, "Be here Monday morning and you can have their jobs". He never got another call.
Those two black brothers were very much a part of my early life. They were the same age range as my father. They had been raised across the creek from my daddy's family. When my daddy, a teenager, bought his first tractor in the later 30's, a used F-20, they went to work for him. They were't well educated and niether was my dad (had to quit school in eighth grade). They worked hard and saved their money and by the late 50's they both lived in brick homes and drove nice cars/trucks and had moved on to better jobs. That was long before civil rights had done anything to change a blacks chances in life around here.
The first 15 years of my life, I probably spent more time with those two black brothers than I did with my daddy. Like a lot of white and black families in the south at that time, we had a very close relationship with them and their familes. They were like a part of our family. Daddy stopped doing public contract work in '55 and they had to get other jobs. He helped them land jobs that blacks couldn't get back then. Daddy stopped public work in '55 due to debt for equipment and a deep recession (like now). I never saw daddy cry but twice...make that 3 times. In 1955 we were about to loose everything and he had to sell a bunch of stuff to get out of debt...he cried...thirty years later, the younger of those 2 brothers died and he cried. A few years later mother died and he cried.
Thanks diesel driver for bringing back fond old memories.