The Scag is a basic machine but very robust
I never see any problems with the Liberty models, higher up the chain the scags use modules that are forever giving customers grief
The Spartan is the highest order mower in its price range & offers the best value for the $ , providing the new Toro made ones are the same as the old ones
They were over engineered & over built to make sure there were no warranty claims & to build a good reputation.
The Big Dog is again a basic mower, well built the only down side is it has a lot of unique parts so only Big Dog blades and if the blade - deck combination does not suit your grass.
Don't be fooled by massive acres/hour as all of them are just the width of the deck & the max forward speed and he onlly time you can mow full speed is in winter when you are only lopping off 1/2".
Most times you are limited by the volume capacity of the deck and the volume capacity of the discharge hole in the deck ( bigger is better )
. Larger wheels and tires make the ride smoother and you get less deck tilting on turns. I struggled looking at Toro, ExMark, Scag, Ferris & Simplicity. I probably could have been happy with any of them but settled on a Simplicity XT ( which is a Ferris design with the striping roller added). With 2-acres you may be inclined to want to more faster than with a smaller property. You have more ground to cover and the tendency with a ZT is to increase ground speed as you mow flat ground. That makes the deck a important factor. Which deck will handle a lot of grass and cut it evenly and discharge it without windrows? Finding one in stock at this time of year could prove to be a challenge as supplies have been limited all season.