I am rather fond of the JD residential ZTR's
For your block a 355 or 400 series .
It is the little things that stand out like al the fasteners you might need to get to when mowing are 8mm metric with a 13mm head and the deck height pin has a 13 mm head built into one end like a tyre wrench.
The deck spindles are bigger & stronger than a lot of commercials and you have a really big choice of blades .
The rear body work unbolts , using that same 13mm wrench to give clean access to the engine the oil filter can be changed without looking like you are a driller on a rig
So the whole mower has that I HAVE BEEN DESIGNED BY SOME ONE WHO KNOWS WHAT THEY DOING feel about it .
Grevelys are quite solid but need 5 tools to do any job
With only 3 acres you mighr be ale to get by with a smaller deck which will reduce the time spent with the weed wacker.
Alternative is to oput some sort of non crowing greound cover around the trees, Sawdust , bark mulch etc etc .
Then it is just a quick spray with your favourite weed killer 3 or 4 times a year