Lawn tractors => yard tractors => sub compact tractors => compact tractors => Small HP tractors
In increasing size & price
A small deck on a powerful mower will cut a lot faster than a big deck will.
The cutting rates quoted are all BS and are usually the maximum speed x deck width , so you can virtually 1/2 most of them .
Bigger diameter wheels slip less than small ones
Lots of old sub compact tractors around there second hand .
Look for ones that have horizontal shaft engines, they are head & shoulders above vertical shaft mowers
Do not buy any Husqvarna "garden tractors " as they are just a lawn tractor pressed out of the next size up plate and are prone to breaking in 1/2 .
Diesels always come with big decks and big decks choke on tall grass which means you have to mow really slowly regardless of the power of the engine .
If you can find an old Troybuilt Dura Force that would be a good starting point
The old 2000 & 3000 series Cub Cadets are magic but the spindles are no longer made , however having proper bearings ( tapered rollers ) if kept greased they should run forever if you remove the grass that accumulates around the blade & wears the bottom away .
Grass Hoppers are also really good .
There is no such things as the universally best mower
You are looking for the right mower for you, your life style, your terrain & your grass
So be preparred to try a dozen or so til you find the one that works for you
So buy some used ones ( two would be a good idea ) and use them for while.
Sell the one that does the worst job & buy another different one .
When you have found what suits you best then look at the current equivalent , if there is one .
Every one will chime in with their favourite mower that they found works for THEM but they are not YOU .
If you are not particularly lawn proud then look at sub compact / compact tractors with a rear PTO deck
Flail mowers are good for long grass that is cut infrequently as they cut it well and distribute the clippings fairly evenly across the full deck width so you don't end up with a lawn full of clipping turds that will sit around for months .