I don't have a favorite brand. I'm a "whatever is worth the money" guy. I always buy used.
As to size, you need to be able to angle the blade 45 degrees and still be wider than your tractor tracks. Might want to experiment with a tape measure or a 2x4 or something similar.
A Box Blade is more aggressive than a rear scraper blade. But if the primary use is driveway maintenance I'd rather have a rear scraper blade.
A Land Plane is a very handy tool for driveway maintenance but isn't capable of doing much else.
Of the three, rear scraper blade, box blade, land plane, rear scraper blade will give you the largest variety of service if only buying one tool.