NWJohn,
It depends on what type of work I am doing with the FEL if I keep the MMM on, and locked in the "Top" position. If I am moving mulch or spreading soil and I have no problem with ground clearance and not in tight spots I leave it on. If I am going to do some real work, I take it off. You will find if you put weight on the 3 pt either via a weight box or tiller or what ever, you will have better traction but MUCH more important, it will be safer to operate when moving from point A to B with a load. Either way, keep the load down low and do not make sharp turns and ALWAYS wear the seat belt, it will keep you in the tractor if it rolls. Even on flat ground with the load too high and a quick turn, it will go over. I had one close call so I can tell you it CAN happen!.
If you are going to do any serious soil removal, get a tooth bar, got one a few weeks ago from Carver for $289 delivered, and boy what a difference. You can do some real moving of soil with it. I found if I dragged the FEL backwards with the teeth digging in I could loosen the soil and then go forward to remove it. Low gear works a lot better then high when pushing or pulling with he FEL. Remember for real serious soil removal a back hoe it what you really need. The FEL is not meant for serious digging past a few inches.
I went through the same as you did, 7500 or BX, at the end of the day after reading all the great posts on TBN, I went with the BX since 90% of what I do is grass cutting. But I must admit sometimes that 7500 would have been nice too!
Enjoy and have fun and be safe.!
Tom