The top end Logans are fine. Expect to pay around $1200 for a new 48" one of those with a squaring arm.
Too small a cutter and you'll be wrestling with it. Fletchers are nice, but more expensive. You need to learn specific techniques to use any any linear matcutter correctly or you won't get truly square corners. None of them are goof proof. A number of pro brands have been made like Keeton and C&H; but most of those will be so old as to probably have wear and tear problems.
And the fact is, some brands of mat board are more consistent, and cut easier than others. But with any linear matcutter, once the thickness of the board itself changes, then you need to reset your blade depth as well as start and end stops. Good board itself is getting quite expensive these days, so there is no sense in skimping on matcutter quality or the blades you need.
To get something truly semi-pro you need to spend around $4000; but most serious shops now have computerized machines costing way more than even that.
I've long coveted an Esterly Speedmat, but can't justify the expense at my age. I once had an early model of that, before they perfected the design. If you have to cut a couple hundred mats in a row, one's finger can get pretty sore with an ordinary linear cutter. The Speedmat system lets you lock in your settings for all four cuts, and then you just rotate the head. Pneumatic plunge options are available for thicker board. If you do large shows or otherwise cut a lot of window mats, this is the way to go. They are used in wall-mount mode, not atop a table. You'll have far less mistakes and waste less board.