Craig, Midwest is my favorite make of non-PTO powered implements largely because they do a good job of balancing price & quality. They have great back blades, box blades and landscape rakes. All the adjustments can be made without tools on their versions with tilt and offset features. There are other brands that have more features like hydraulic lifts, rollover blades, etc. Midwest makes the blades under their own brand name, as well as private lable units for large dealers and for manufacturers such as Kioti. They are made in Illinois. They make 3 series of box blades, the 15 series, which is the lighter weight units for sub-CUTS and small CUTs (but they are still very well made). The 20 series which is their standard duty line. The 30 series which is their heavy duty stuff. All appear to be made to the highest standards, the 30 series is just bigger, badder and heavier.
On some of their lines (like rakes) they substitute the "0" for a "2" on some products, so a "22" would be a "20" series and the second "2" means it has the tilt feature.
While there is a lot of talk about Midwest, there are some other excellent brands out there. Befco is awesome (and I think they have the best rear finish mowers on the market). Bush Hog, Gannon, Land Pride are among some of the other premium brands. With box blades you really want the heaviest thing you can buy (within reason) and use effectively with your tractor. Look at the brands your dealer sells, any of the good brands will serve you well. Box blades all look similar, but it is not uncommon to find the lower priced brands weigh 100# to 125# less than the premium brands of identical size.